Peak Index in a Mountain Array LeetCode Solution

Difficulty Level Medium
Frequently asked in Amazon Apple Bloomberg Facebook Google Microsoft YahooViews

Problem Statement

Peak Index in a Mountain Array LeetCode Solution – An array arr a mountain if the following properties hold:

  • arr.length >= 3
  • There exists some i with 0 < i < arr.length - 1 such that:
    • arr[0] < arr[1] < ... < arr[i - 1] < arr[i]
    • arr[i] > arr[i + 1] > ... > arr[arr.length - 1]

Given a mountain array arr, return the index i such that arr[0] < arr[1] < ... < arr[i - 1] < arr[i] > arr[i + 1] > ... > arr[arr.length - 1].

You must solve it in O(log(arr.length)) time complexity.

Input: arr = [0,1,0]
Output: 1

Explanation

The mountain increases until it doesn’t. The point at which it stops increasing is the peak.

Peak Index in a Mountain Array LeetCode SolutionPin

For this problem, we are trying to find a index where a[mid] > a[mid -1] AND a[mid] > a[mid + 1]. That is what the definition of a peak is.

We can use binary search to do this in O(log n) time, but before we go on we need to set up some ground rules on what values we will land on, and what do they mean.

There are four different scenarios we need to take into consideration

  • We land on the peak where a[mid] > a[mid – 1] and a[mid] > a[mid +1]
  • We land in a valley where a[mid] < a[mid-1] and a[mid] < a[mid + 1]
  • We land on a slope, and need to see which way is facing towards a peak (this point is the last two scenarios)

It’s also very important to point out that index 0 or index a.length – 1 can be a peak as well! So we need some custom logic in here for that.

Code

Java Code for Peak Index in a Mountain Array:

class Solution {
    public int peakIndexInMountainArray(int[] arr) {
        int start = 0;
        int end = arr.length - 1;

        while (start < end) {
            int mid = start + (end - start) / 2;

            if(arr[mid]>arr[mid+1]){
                end = mid;
            }else if (arr[mid]<arr[mid+1]){
                start = mid+1;
            }

        }
        return start;
    }
}

Python Code for Peak Index in a Mountain Array:

class Solution(object):
    def peakIndexInMountainArray(self, arr):
        start = 0
        end = len(arr)-1

        while start<=end:
            mid = (start+end)//2
            if start==end:
                return mid
            elif arr[mid] > arr[mid+1]:
                end = mid
            else:
                start = mid+1

Complexity Analysis for Peak Index in a Mountain Array LeetCode Solution

Time Complexity

O(logn), where N is the length of the Array as we are doing binary search.

Space Complexity

O(1), as we are not using any extra space.

Top Interview Questions

S.No Interview Question Number of times has been asked
1Delete a node in doubly linked list2831
2Java program to find the number of Nodes in a Binary Tree2508
3Reverse a string without affecting special characters2469
4Delete a node of a linked list at given position1982
5Palindrome using Recursion1882
6Insert nodes in a linked list in a sorted way (Ascending Order)1668
7Find elements pair from array whose sum equal to number1655
8Sort Elements by Frequency of Occurrences1640
9Write a program to print all permutations of a given string1614
10Quick Sort1545
11Find Minimum Distance Between Two Numbers in an Array1479
12Create a Doubly Linked List1454
13Reverse an Array1417
14Smallest window in a string containing all characters of another string1402
15Find a Triplet That Sum to a Given Value1364
16Recursively remove all adjacent duplicates1362
17First Repeating Element1346
18Arrange Even and Odd number such that Odd comes after Even1327
19Sum of numbers in String1324
20Smallest Positive Number Missing in an Unsorted Array1292
21Check if the Elements of an Array are Consecutive1261
22Detect a loop in the Linked List1246
23Largest Sum Contiguous Subarray1235
24Quick Sort on SIngly Linked List1223
25Subarray with Given Sum1217
26Print all Possible Combinations of R Elements in a given Array of size N1208
27Recursive function to do substring search1206
28Find the Maximum Repeating Number in Array1160
29Binary Tree Level order traversal in Java1130
30Find the First and Second Smallest Elements1126
31Check if two linked lists are identical1112
32Maximum Subarray Sum using Divide and Conquer1108
33Remove characters from first string which are in second1075
34Find Leaders in an Array1064
35Swap nodes in the linked list1043
36Find the Number Occurring Odd Number of Times in an Array1008
37Arrange given Numbers to Form the Biggest Number II997
38Find the second most frequent character994
39Given a string find its first non-repeating character975
40Find Triplet in Array With a Given Sum968
41Total number of occurrences of a given item in the linked list959
42Given a sorted array and a number x, find the pair in array whose sum is closest to x959
43A Program to check if strings are rotations of each other or not952
44Print all possible words from phone digits939
45Find the Missing Number930
46Rearrange Positive and Negative Numbers Alternatively in Array925
47Longest Palindromic Substring910
48Segregate even and odd nodes in a linked list892
49Print Longest common subsequence887
50Union and Intersection of Two Linked Lists879
51Transform one string to another using minimum number of given operations873
52Check rearranged string can form a palindrome855
53Rearrange given Array in Maximum Minimum Form851
54Iterative Implementation of Quick Sort839
55Count Possible Triangles825
56Multiplication of Two Matrices808
57Check if the linked list is palindrome801
58Rotate a Linked List800
59Count of Triplets With Sum Less than Given Value800
60Stock Buy Sell to Maximize Profit797
61Insertion Sort770
62Concatenation of two strings768
63Tug of War766
64Print all duplicates in the input string762
65Count Number of Substrings with K Distinct Character’s761
66Find Nearest Greater and Smaller Element750
67The Celebrity Problem744
68Find Pythagorean Triplets from Array742
69Remove ‘b’ and ‘ac’ from a given string737
70Reverse String Without Temporary Variable737
71Find all Common Elements in Given Three Sorted Arrays734
72Remove all duplicates in an unsorted linked list714
73Find the Row with Maximum Number of 1’s712
74Find the Peak Element from an Array704
75Find the subarray whose sum is equal to a given number X701
76Remove Minimum Characters so that Two Strings Become Anagrams697
77Addition of Two Matrices691
78Find Smallest Missing Number in a Sorted Array691
79A Product Array Puzzle689
80Generate all Binary Strings Without Consecutive 1’s683
81Implement Two Stacks in an Array681
82Maximum Sum of Non Consecutive Elements675
83Maximum Product Subarray II661
84Lexicographic rank of string661
85Check if Two given Matrices are Identical653
86Multiplication of Previous and Next653
87Subtraction of Two Matrices641
88Merge K Sorted Arrays and Print Sorted Output638
89Move All the Zeros to the End of the Given Array637
90Divide a string in N equal parts631
91Online Algorithm for Checking Palindrome in a Stream629
92Form Minimum Number from Given Sequence of D’s and I’s628
93Remove recurring digits in a given number622
94Check whether two strings are anagram of each other621
95Maximum Circular Subarray Sum616
96Sort a linked list that is sorted alternating ascending and descending615
97Sort a stack using a temporary stack613
98Find the Minimum Element in a Sorted and Rotated Array610
99Move last element of the Linked List at first place610
100Subarray and Subsequence606
101First Circular Tour to Visit all the Petrol Bunks604
102Largest Subarray with Equal Number of 0’s and 1’s602
103Compare two strings(linked lists)599
104Flattening a linked list599
105Maximum Element in an Array which is Increasing and then Decreasing595
106Palindrome Permutations of a String591
107Palindromes in a given range584
108Elements Appear more than N/K times in Array584
109Print all permutations with repetition583
110Majority Element582
111Run length encoding582
112Pangram Checking578
113Minimum insertions to form a shortest palindrome578
114Minimum Characters to be Added at Front to Make String Palindrome570
115Merge a linked list into another at alternate positions570
116Rearrange a given linked list in-place569
117Most repeating character in a string569
118Remove all duplicates in a sorted linked list569
119Minimum number of Merge Operations to make an Array Palindrome567
120Rotate string to get lexicographically minimum string564
121Repeated Subsequence of Length Two or More561
122Print all anagrams together in a sequence of words559
123Reorder an Array According to the Given Indexes557
124Pancake Sorting Problem546
125Two Sum Leetcode Solution544
126Clone a Linked List with next and random pointer542
127Merge Overlapping Intervals II542
1283Sum Leetcode Solution539
129Transpose of a Matrix533
130Size of The Subarray With Maximum Sum532
131Remove Extra Spaces from a String529
132Removing Spaces from a String using stringstream527
133Remove duplicates from a string526
134Check if a given string is a rotation of a palindrome525
135Partition Problem524
136Smallest Palindrome after Replacement523
137Maximum Sum Increasing Subsequence522
138Longest Palindrome can be Formed by Removing or Rearranging Characters522
139Check whether Strings are K Distance Apart or Not514
140Generate all Binary Strings from Given Pattern510
141Length of Longest valid Substring508
142Find Zeros to be Flipped so that Number of Consecutive 1’s is Maximized506
143Insert Node in the Sorted Linked List505
144Delete Last Occurrence504
145Check if Two given Strings are Isomorphic to each other500
146Maximum difference between two elements such as larger element comes after smaller494
147Program to Toggle all Characters in a String492
148Given string is interleaving of two other strings or not489
149Count Minimum Steps to Get the given Array485
150Merge sort better than quick sort for linked lists482
151Number of Smaller Elements on Right Side481
152Find Pair with Given Difference480
153Check length of a String is Equal to the Number Appended at its Last479
154Check if all Rows of a Matrix are Circular Rotations of Each Other477
155Longest Common Prefix using Divide and Conquer475
156Find nth node of the Linked list from the end473
157Find a Fixed Point in a Given Array467
158Sort 0s 1s and 2s in an Array466
159Print all interleavings of given two strings464
160Compare Two Version Numbers464
161Reverse words in a given string462
162Find the Subarray of given length with Least Average461
163Merge two sorted linked lists such that merged list is in reverse order459
164Reorder Array Using Given Indexes459
165Print Reverse of a string (Recursion)459
166Split linked list using alternate nodes457
167Median of Two Sorted Arrays LeetCode Solution456
168Print string of odd length in ‘X’ format445
169Print all Palindromic Partitions of a String440
170Find K Length Subarray of Maximum Average440
171Find Element Using Binary Search in Sorted Array439
172Swap Kth Node from beginning with Kth Node from End437
173Find Duplicates in an Array in Most Efficient Way433
174print all palindromic partitions426
175Flatten a multilevel linked list423
176Shortest Superstring Problem421
177Maximum Length of Chain Pairs420
178Check if String Follows Order of Characters by a Pattern or not418
179Sorting a K Sorted Array415
180Sort a String According to Another String412
181Longest Span with same Sum in two Binary Arrays II404
182Reverse a Linked List in groups401
183Find a Sorted Subsequence of size 3400
184Recursively print all the sentences that can be formed from list of word lists398
185Program to add two binary digits397
186Find the two Numbers with Odd Occurrences in an Unsorted Array393
187Longest Common Prefix Using Binary Search II392
188Reverse a Singly Linked List (Iterative/Non-Recursive)389
189Caesar Cipher388
190Kth Non-repeating Character386
191Rearrange a linked list in Zig-Zag384
192Check if String can Become Empty by Recursively Deleting given Substring383
193Rotate Image by 90 degrees380
194Longest Common Prefix Word by Word Matching380
195Pancake Sorting380
196Permutations of a Given String Using STL373
197Perfect Reversible String371
198Merging Two Sorted Arrays368
199Increasing Subsequence of Length three with Maximum Product368
200Sort a linked list with 0s, 1s and 2s365
201Find First non-repeating character in a string365
2021`s and 2`s complement of binary number365
203Find the point where a monotonically increasing function becomes positive first time364
204Construct a Maximum Sum Linked List out of two Sorted Linked Lists having some Common nodes363
205Four Elements that Sum to Given362
206List items containing all characters of a given word360
207Delete N nodes after M357
208Longest Common Prefix using Character by Character Matching353
209Count Number of Occurrences in a Sorted Array351
210Palindrome string (number)349
211Split a string347
212Minimum Characters to be Removed to Make a Binary String Alternate343
213Recursive Implementation of atoi()341
214Check if a Linked list of Strings form a Palindrome340
215Print All Distinct Elements of the Array338
216Sorting the array of strings337
217Even Substring Count336
218Maximum occurring character in a string334
219Convert a String that is Repetition of a Substring of Length K334
220Find the first Repeating Number in a Given Array333
221Valid Parentheses LeetCode Solution333
222Reverse a singly linked list recursively331
223Print Shortest Path to Print a String on Screen329
224Can we reverse a linked list in less than O(n) time ?329
225Convert string1 to string2 in one edit327
226Reverse a String using Stack326
227Binary Tree to Doubly linked list326
228wildcard character matching325
229Nth Character in Concatenated Decimal String323
230Sort Elements by Frequency II323
231Maximum Subarray Leetcode Solution321
232Count the number of words318
233Lower Case To Upper Case318
234Merge Two Sorted Arrays316
235Split Four Distinct Strings315
236Find the Lost Element From a Duplicated Array313
237Find middle of the Linked List311
238Longest Common Subsequence with Permutations309
239Count the Pairs at Same Distance as in English Alphabets307
240Matrix Chain Multiplication using Dynamic Programming302
241Next Greater Element in an Array301
242Palindrome Permutation295
243Roman to Integer Leetcode Solution292
244Find Nth Node291
245Find All Pairs With a Given Difference290
246Searching a node in a Binary Search Tree288
247Triplet from three linked lists with given sum286
248Delete a Tree283
249Reverse a String283
250String(represents an integer) to value283
251Reverse Bits281
252Word Search Leetcode Solution281
253Delete a node under given conditions280
254Print all Possible Ways to Break a String in Bracket Form280
255Binary Tree278
256Change Gender of a given String278
257How to Efficiently Implement k Stacks in a Single Array?275
258Sort an array of strings275
259First non Repeating Element274
260Count Pairs With Given Sum273
261Meeting Rooms II LeetCode Solution271
262Longest Common Extension271
263Number of sub-strings which recursively add up to 9271
264Toeplitz Matrix270
265Remove middle points in a linked list of line segments270
266Repeated Substring Pattern269
267Move all negative elements to one side of array269
268N queen problem268
269Longest Palindromic Substring LeetCode Solution266
270Remove spaces from a string266
271Shuffle a given Array264
272Min Stack262
273Number of Islands LeetCode Solution260
274Cuckoo sequence program259
275Dijkstra Algorithm257
276House Robber Leetcode Solution256
277Max stack256
278Find, second, frequent, character255
279Minimize the maximum difference between the heights254
280Most Frequent Element in an Array254
281Clone a linked list with next and random pointer (Hashing)252
282Search Insert Position Leetcode Solution251
283Fibonacci numbers250
284Expression Evaluation250
285Sort linked which is sorted on absolute values249
286Sudoku Solver247
287Plus One Leetcode Solution247
288Valid Palindrome Leetcode Solution247
289Subset Leetcode247
290KMP Algorithm246
291Number Of 1 bits246
292Word Search245
293Combination Sum Leetcode Solution245
294Reverse words in a string244
295How to Delete a Linked List244
296Evaluation of Postfix Expression244
297Min Stack Leetcode Solution243
298Backspace String Compare239
299Set Matrix Zeroes237
300Merge Sorted Arrays Leetcode Solution236
301Sqrt(x) Leetcode Solution236
302Reversing a Queue235
303Rabin Karp Algorithm234
304Pair of Positive Negative Values in an Array234
305Common elements in all rows of a given matrix233
306Subarray with 0 sum233
307Tower Of Hanoi231
308Delete middle element of a stack230
309Contains Duplicate II Leetcode Solution230
310Product of array except self229
311Intersection of Two Arrays II Leetcode Solution228
312Combination Sum228
313Integer to Roman Leetcode Solution228
314String Compression227
315Pascal Triangle Leetcode227
316Reverse individual words225
317Count subarrays with equal number of 1’s and 0’s225
318Minimum swaps required to bring all elements less than or equal to k together224
319Bellman Ford Algorithm224
320Implementation of Deque using Doubly Linked List224
321Count of index pairs with equal elements in an array224
322Find Top K (or Most Frequent) Numbers in a Stream223
323Sliding Window Technique223
324Single Number Leetcode Solution223
325Construct Binary Tree from Given Inorder and Preorder Traversals222
326Add Binary Leetcode Solution221
327Minimum Value to Get Positive Step by Step Sum Leetcode Solution221
328Arithmetic Expression Evaluation221
329Contains Duplicate220
330Segregate even and odd numbers220
331Sort elements by frequency220
332Second Most Repeated Word in a Sequence219
333Pow(x, n) Leetcode Solution219
334Page Replacement Algorithms in Operating Systems219
335Palindrome Linked List Leetcode Solution219
336Postfix to Infix Conversion218
337Find sum of non-repeating elements (distinct) elements in an array218
338Group Words With Same Set of Characters217
339Design a stack that supports getMin() in O(1) time and O(1) extra space217
340Count Odd Numbers in an Interval Range Leetcode Solution217
341Next Permutation217
342Smallest Subarray with k Distinct Numbers216
343Maximum Number of Balloons Leetcode Solution216
344Kruskal Algorithm216
345Third Maximum Number Leetcode Solution215
346Convex Hull Algorithm214
347Scramble String214
348Permutations Leetcode Solution213
349Find Lucky Integer in an Array Leetcode Solution213
350Top K Frequent Words213
351Sum of minimum and maximum elements of all subarrays of size k213
352K-th Smallest Element in a Sorted Matrix213
353Longest Substring Without Repeating Characters LeetCode Solution213
354Minimum operation to make all elements equal in array212
355Find the Town Judge Leetcode Solution212
356Longest Common Prefix Leetcode Solution211
357Sorting array using Stacks211
358Find Numbers with Even Number of Digits Leetcode Solution211
359Maximum Subarray211
360Evaluate Division210
361Majority Element Leetcode Solution210
362Count subarrays having total distinct elements same as original array209
363First element occurring k times in an array209
364Special Number209
365Given two unsorted arrays find all pairs whose sum is x208
366Number of Good Pairs Leetcode Solution208
367Spiral Matrix LeetCode Solution208
368Prefix to Infix Conversion207
369Huffman Coding207
370Swap Nodes in Pairs Leetcode Solutions207
371Minimum Path Sum207
372Reverse a Number Using Stack206
373Check if two arrays are equal or not206
374Missing Number Leetcode Solution206
375Pascal’s Triangle II Leetcode Solution206
376Search in Rotated Sorted Array Leetcode Solution205
377Count Primes Leetcode Solutions205
378Reversing the First K elements of a Queue205
379Merge Two Sorted Lists Leetcode Solutions205
380Best Time to Buy and Sell Stock  II Leetcode Solution205
381Single Number204
382Sort Array by Increasing Frequency Leetcode Solution204
383Minimum Steps to reach target by a Knight204
384Find duplicates in a given array when elements are not limited to a range204
385Minimum Absolute Difference Leetcode Solution204
386Group Anagrams203
387Maximal Square203
388Power of Two Leetcode Solution203
389Top K Frequent Elements202
390Find All Numbers Disappeared in an Array Leetcode Solution202
391House Robber II Leetcode Solution202
392Matrix Diagonal Sum Leetcode Solution202
393Fizz Buzz Leetcode201
394Maximum possible difference of two subsets of an array201
395Unique Paths Leetcode Solution201
396Maximum Distance Between two Occurrences of Same Element in Array201
397Sorting using trivial hash function201
398Convert String To Int201
399Running Sum of 1d Array Leetcode Solution201
400How to Implement Stack Using Priority Queue or Heap?200
401Find Minimum In Rotated Sorted Array200
402Average Salary Excluding the Minimum and Maximum Salary Leetcode Solution200
403Expression Contains Redundant Bracket or Not200
404How Many Numbers Are Smaller Than the Current Number Leetcode Solution199
405Max Consecutive Ones Leetcode Solution199
406Subarray Sum Equals k199
407Range Sum Query 2D – Immutable Leetcode Solution199
408Unique Paths199
409Zigzag Conversion199
410Find the first repeating element in an array of integers199
411Happy Number Leetcode Solution198
412Check if Array Contains Contiguous Integers With Duplicates Allowed198
413Coin Change 2 Leetcode Solution198
414Smallest Element Repeated Exactly K Times198
415Find Number of Employees Under every Employee198
416Find the Closest Palindrome number198
417Leetcode Permutations198
418Sort Integers by The Number of 1 Bit Leetcode Solution198
419Subset sum problem197
420Cumulative Frequency of Count of Each Element in an Unsorted Array197
421Decode String197
422Subarray Sum Equals K LeetCode Solution197
423Difference between highest and least frequencies in an array197
424Find Winner on a Tic Tac Toe Game Leetcode Solution197
425Palindrome Substring Queries197
426Letter Case Permutation197
427Length of the largest subarray with contiguous elements196
428Reverse Integer196
429Best Time to Buy and Sell Stock III Leetcode Solution196
430Monotonic Array LeetCode Solution196
431Remove Duplicates from Sorted Array Leetcode Solution196
432Print All Distinct Elements of a Given Integer Array196
433Find top three repeated in array195
434Implement Stack and Queue using Deque195
435Sort a stack using recursion195
436Nth Catalan Number194
437Generate a String With Characters That Have Odd Counts Leetcode Solution194
438Capacity To Ship Packages Within D Days Leetcode Solution194
439Fibonacci Number LeetCode Solution194
440Reverse Vowels of a String Leetcode Solution194
441Count Substrings with equal number of 0s, 1s and 2s194
442Find The Duplicate Number193
443Sum of Subarray Ranges Leetcode Solution193
444Reverse a Stack Using Recursion193
445Print all subarrays with 0 sum193
446LRU Cache Implementation193
447Subtract the Product and Sum of Digits of an Integer Leetcode Solution193
448Maximum Depth of Binary Tree Leetcode Solution193
449Reverse Words in a String III LeetCode Solution193
450Find Median from data Stream193
451Shuffle the Array Leetcode Solution192
452Integer to English words192
453Subarrays with distinct elements192
454Trapping Rain Water Leetcode Solution192
455Bipartite Graph192
456Check If N and Its Double Exist Leetcode Solution192
457Delete a Node from linked list without head pointer192
458Prim’s Algorithm192
459Find the Duplicate Element191
460Merge Two Sorted Linked Lists191
461Sorting a Queue without Extra Space190
462Target Sum190
463Iterative Tower of Hanoi190
464Find the Difference Leetcode Solution190
465Priority Queue Using Singly Linked List190
466Excel Sheet Column Number Leetcode Solution190
467Reverse a String190
468Find Common Characters Leetcode Solution190
469Kth largest element in an Array Leetcode Solutions190
470Longest Common Subsequence189
471Fizz Buzz189
472Balanced Binary Tree Leetcode Solution189
473Edit Distance189
474Find all pairs (a, b) in an array such that a % b = k189
475Count and Say188
476Count pairs from two linked lists whose sum is equal to a given value188
477Minimum Moves to Equal Array Elements Leetcode Solution188
478Kids With the Greatest Number of Candies Leetcode Solution188
479Concatenation of Array LeetCode Solution188
480Reverse a linked list187
481Floyd Warshall Algorithm187
482Find First and Last Position of Element in Sorted Array Leetcode Solution187
483Next Greater Element I Leetcode Solution187
484Kth Largest Element in a Stream Leetcode Solution187
485Longest Common Prefix using Trie187
486Degree of an array187
487The K Weakest Rows in a Matrix Leetcode Solution187
488Remove Minimum Number of Elements Such That no Common Element Exist in both Array187
489Word Ladder LeetCode Solution187
490Number of Steps to Reduce a Number to Zero Leetcode Solution187
491Find elements which are present in first array and not in second187
492Shortest Palindrome186
493Design Parking System Leetcode Solution186
494Merge Overlapping Intervals186
495Text Justification LeetCode Solution186
496Find subarray with given sum (Handles Negative Numbers)186
497Prefix to Postfix Conversion185
498Count and Say Leetcode Solution185
499MiniMax Algorithm185
500Slowest Key Leetcode Solution185
501Zigzag Conversion LeetCode Solution185
502Multiply Strings Leetcode Solution185
503Flood Fill LeetCode185
504Find four elements that sum to a given value (Hashmap)185
505Move Zeroes LeetCode Solution184
506Max Area of Island184
507Valid Parenthesis String184
508Find N Unique Integers Sum up to Zero Leetcode Solution184
509Top View of Binary Tree184
510Jump Game Leetcode Solution184
511Longest subarray not having more than K distinct elements184
512Priority Queue in C++183
513Find any one of the multiple repeating elements in read only array183
514Pair with given product183
515Recursion183
516Substring With Concatenation Of All Words183
517Mobile Numeric Keypad Problem183
518Find distinct elements common to all rows of a matrix183
519Length of Last Word Leetcode Solution183
520Next Greater Frequency Element183
521Peak Index in a Mountain Array183
522Convert array into Zig-Zag fashion183
523The Stock Span Problem183
524Implement a stack using single queue182
525Iterative Inorder Traversal of a Binary Tree182
526Intersection of Two Arrays182
527Longest Common Prefix using Sorting182
528Count number of triplets with product equal to given number182
529Check if a given array contains duplicate elements within k distance from each other182
530Shuffle String Leetcode Solution182
531Excel Sheet Column Title Leetcode Solution181
532Find missing elements of a range181
533Relative Sort Array Leetcode Solution181
534Delete Node in a Linked List Leetcode Solution181
535Postfix to Prefix Conversion181
536Find Index of Closing Bracket for a Given Opening Bracket in an Expression181
537Largest Sum Contiguous Subarray181
538Last Stone Weight181
539Implement Stack using Queues180
540Smallest Subarray With all Occurrences of a Most Frequent Element180
541Koko Eating Bananas Leetcode Solution180
542Contiguous Array Leetcode180
543Is Subsequence Leetcode Solution179
544Convert a normal BST to Balanced BST179
545N-th Tribonacci Number Leetcode Solution179
546Minimum Bracket Reversals178
547Container with Most Water178
548Rearrange a binary string as alternate x and y occurrences178
549K-th Distinct Element in an Array178
550Isomorphic Strings Leetcode Solution178
551Change the Array into Permutation of Numbers From 1 to N178
552Implementation of Deque using circular array178
553Best Time to Buy and Sell Stock178
554Group Multiple Occurrence of Array Elements Ordered by first Occurrence178
555Distribute Candies to People Leetcode Solution178
556Linked List Cycle II LeetCode Solution178
557Build Array From Permutation Leetcode Solution177
558Find Words That Can Be Formed by Characters Leetcode Solution177
559Minimum Operations to convert X to Y177
560Gold Mine Problem177
561Jewels and Stones Leetcode Solution177
562First negative integer in every window of size k177
563Check for Balanced Parentheses in an Expression177
564Integer to Roman177
565Valid Sudoku177
566Assign Cookies Leetcode Solution177
567Convert Sorted Array to Binary Search Tree Leetcode Solution177
568Sum of Left Leaves Leetcode Solutions177
569Largest Perimeter Triangle Leetcode Solution177
570Valid Anagrams177
571Minimum Knight Moves LeetCode Solution176
572Combinations Leetcode Solution176
573Island Perimeter Leetcode Solution176
574Remove Linked List Elements Leetcode Solution176
575Unique Binary Search Trees176
576Arrange given numbers to form the biggest number176
57701 Matrix LeetCode Solution176
578Shuffle an Array176
579Hamming Distance176
580Count all subsequences having product less than K175
581Rotate List Leetcode Solution175
582The Knapsack Problem175
583Summary Ranges Leetcode Solution175
584Trapping Rain Water LeetCode Solution175
585Minimum Delete Operations to make all Elements of Array Same175
586Count the number of nodes at given level in a tree using BFS174
587Maximum sum rectangle in a 2D matrix174
588LRU Cache LeetCode Solution174
589Decode Ways174
590Maximum Distance in Array173
591Find the smallest positive integer value that cannot be represented as sum of any subset of a given array173
592Insert Interval Leetcode Solution173
593Maximum path sum in a triangle173
5943Sum Closest LeetCode Solution173
595Shortest Path in a Grid with Obstacles Elimination LeetCode Solution173
596Maximum Number of Chocolates to be Distributed Equally Among k Students173
597Distance Between Bus Stops Leetcode Solution173
598Minimum number of distinct elements after removing m items172
599Stone Game LeetCode171
600Rotate Image LeetCode Solution171
601Find minimum difference between any two elements171
602Minimum insertions to form a palindrome with permutations allowed171
603Same Tree LeetCode Solution171
604Sieve of Eratosthenes171
605Sort Characters By Frequency LeetCode Solution171
606Replace Elements with Greatest Element on Right Side Leetcode Solution171
607Minimum number of subsets with distinct elements171
608How to check if two given sets are disjoint?171
609Permutation in String Leetcode Solution171
610Word Wrap Problem170
611Applications of Breadth First Search and Depth First Search170
612XOR Operation in an Array Leetcode Solution170
613Painting Fence Algorithm170
614Frog Jump Leetcode Solution170
615K Empty Slots LeetCode170
616Sort Array By Parity LeetCode Solution170
617Remove All Occurrences of a Substring LeetCode Solution170
618Find if an Expression has Duplicate Parenthesis or Not170
619Word Pattern170
620Smallest Good Base170
621Reverse a stack without using extra space in O(n)170
622Bubble sort using two Stacks170
623Tracking current Maximum Element in a Stack169
624Isomorphic Strings169
625Distance of nearest cell having 1 in a binary matrix169
626Best Time to Buy and Sell Stock LeetCode Solution169
627Minimum Depth of Binary Tree Leetcode Solution169
628Defanging an IP Address Leetcode Solution169
629Printing brackets in Matrix Chain Multiplication Problem169
630House Robber169
631Maximum Consecutive Numbers Present in an Array169
632License Key Formatting Leetcode Solution168
633Find Sum of all unique sub-array sum for a given array168
634Longest Increasing Subsequence168
635Segregate 0s and 1s in an Array168
636Non-overlapping sum of two sets168
637Minimum Cost to Hire K Workers168
638Longest Substring with At Most K Distinct Characters LeetCode Solution168
639Find the Duplicate Number LeetCode Solution168
640Wiggle Sort168
641Moving Average from Data Stream Leetcode Solution167
642Optimal Account Balancing LeetCode Solution167
643Binary Tree Zigzag Level Order Traversal LeetCode Solution167
644Find Maximum Level sum in Binary Tree167
645Count Good Nodes in Binary Tree Leetcode Solution167
646Coin Change Problem167
647Maximum difference between first and last indexes of an element in array167
648Sum of All Odd Length Subarrays Leetcode Solution167
649Valid Palindrome II Leetcode Solution167
650Iterative Method to find Height of Binary Tree167
651How to Create Mergable Stack?167
652Minimum Number of Steps to Make Two Strings Anagram Leetcode Solutions166
653GCD Of Two Numbers166
654Check If It Is a Straight Line Leetcode Solution166
655Queries for counts of array elements with values in given range166
656Kth Missing Positive Number Leetcode Solution166
657Strobogrammatic Number LeetCode Solution166
658Employee Free Time LeetCode Solution166
659Best Time to Buy and Sell Stock with Cooldown Leetcode Solution166
660Merge Two Balanced Binary Search Trees166
661Maximum Number of Occurrences of a Substring Leetcode Solution166
662Find the Distance Value Between Two Arrays Leetcode Solution165
663Find Largest d in Array such that a + b + c = d165
664Valid Palindrome165
665Flipping an Image LeetCode Solution165
666Letter Combinations of a Phone Number165
667Number of Provinces Leetcode Solution165
668Reorganize String165
669Path With Maximum Minimum Value LeetCode Solution165
670Convert an array to reduced form165
671Longest Substring with At Least K Repeating Characters LeetCode Solution165
672Delete consecutive same words in a sequence164
673Partition Labels LeetCode Solution164
674Maximum Number of Coins You Can Get Leetcode Solution164
675Find pairs with given sum such that elements of pair are in different rows164
676Populating Next Right Pointers in Each Node163
677Partition Array Into Three Parts With Equal Sum Leetcode Solution163
678Reducing Dishes LeetCode Solution163
679Power of Four Leetcode Solution163
680Longest Increasing Path in a Matrix LeetCode Solution163
681Print the Fibonacci numbers in reverse order163
682Number of Dice Rolls With Target Sum LeetCode Solution163
683Valid Perfect Square Leetcode Solution163
684Recover Binary Search Tree163
685K Empty Slots163
686Permutation Sequence LeetCode Solution163
687Rearrange an array in order – smallest, largest, 2nd smallest, 2nd largest163
688Edit Distance LeetCode Solution163
689Factorial Trailing Zeroes Leetcode Solution163
690Check If Two String Arrays are Equivalent Leetcode Solution163
691Inorder Successor of a node in Binary Tree163
692Sort Array by Increasing Frequency Leetcode Solution162
693Lucky Numbers in a Matrix Leetcode Solution162
694BFS vs DFS for Binary Tree162
695Check if a queue can be sorted into another queue using a stack162
696Merge Two Binary Trees LeetCode Solution162
697Construct BST from given Preorder Traversal162
698String to Integer (atoi) LeetCode Solution162
699Increasing Decreasing String Leetcode Solution162
700To Lower Case Leetcode Solution162
701Maximum Product of Two Elements in an Array Leetcode Solution162
702Form minimum number from given sequence162
703Dynamic Programming Basics162
704Remove Invalid Parentheses Leetcode Solution162
705Subset Sum Leetcode161
706Ugly Number Leetcode Solution161
707Convert a Number to Hexadecimal Leetcode Solution161
708Reversing a Queue using Recursion161
709Reverse Only Letters LeetCode Solution161
710Binary Tree zigzag level order Traversal161
711Robot Room Cleaner Leetcode Solution161
712Reservoir Sampling161
713Find the Smallest Divisor given a Threshold Leetcode Solution161
714Unique Paths II Leetcode Solution161
715Find whether an array is subset of another array161
716Keyboard Row Leetcode Solution160
717Restore IP Addresses Leetcode Solution160
718Majority Element II Leetcode Solution160
719Delete Nth node from the end of the given linked list160
720Binomial Coefficient160
721Find Leaves of Binary Tree LeetCode Solution160
722Perform String Shifts Leetcode159
723Numbers with prime frequencies greater than or equal to k159
724Bulb Switcher LeetCode Solution159
725Find the largest multiple of 3159
726Add and Search Word – Data structure design LeetCode159
727Decompress Run-Length Encoded List Leetcode Solution159
728Check if Two Expressions With Brackets are Same159
729Find the node with minimum value in a Binary Search Tree159
730Hamming Distance Leetcode Solution158
731Minimum Cost For Tickets Leetcode Solution158
732Sum of f(a[i], a[j]) over all pairs in an array of n integers158
733Find Pair with Greatest Product in Array158
734Race Car LeetCode Solution158
735Number of Islands II LeetCode Solution158
736Morris Traversal158
737Finding K closest element158
738Maximum 69 Number Leetcode Solution158
739Maximum Product of Three Numbers LeetCode Solution158
740Rank Transform of an Array Leetcode Solution157
741String Compression LeetCode Solution157
742Minimum Distance Between BST Nodes Leetcode Solution157
743Student Attendance Record I Leetcode Solution157
744Merge K Sorted Linked Lists157
745Diagonal Traversal of Binary Tree157
746Word Pattern LeetCode Solution157
747Generate all possible sorted arrays from alternate elements of two given sorted arrays157
748Find Maximum Depth of Nested Parenthesis in a String157
749Invert Binary Tree LeetCode Solution157
750Sorted Linked List to Balanced BST157
751First Unique Character in a String LeetCode Solution157
752Tiling Problem157
753Maximum Depth of N-ary Tree Leetcode Solution157
754Best Meeting Point LeetCode Solution156
755Minimum time required to rot all oranges156
756Largest subarray with equal number of 0s and 1s156
757Non-decreasing Array LeetCode Solution156
758Kth ancestor of a node in binary tree156
759Check If Array Pairs Are Divisible by k LeetCode Solution156
760Minimum Height Trees156
761Symmetric Tree Leetcode Solution156
762Find if Path Exists in Graph Leetcode Solution156
763Remove brackets from an algebraic string containing + and – operators156
764Queue based approach for first non-repeating character in a stream156
765Longest Span with same Sum in two Binary arrays156
766Special Array With X Elements Greater Than or Equal X Leetcode Solution156
767Find All Duplicates in an Array LeetCode Solution156
768Find unique character in a string156
769Remove Nth Node From End of List Leetcode Solution156
770Binary Tree Maximum Path Sum LeetCode Solution156
771Partition to K Equal Sum Subsets Leetcode Solution155
772Minimize Maximum Pair Sum in Array LeetCode Solution155
773Final Prices With a Special Discount in a Shop Leetcode Solution155
774Snakes and Ladders LeetCode Solution155
775Find Median from Data Stream LeetCode Solution155
776Largest rectangular sub-matrix whose sum is 0155
777Elements to be added so that all elements of a range are present in array155
778Largest Rectangle in Histogram LeetCode Solution155
779Maximum Length of a Concatenated String with Unique Characters Leetcode Solution155
780Search a 2D Matrix II Leetcode Solution155
781Stack Permutations (Check if an array is stack permutation of other)155
782Evaluate Reverse Polish Notation LeetCode Solution155
783Jump Game155
784Valid Number154
785Count items common to both the lists but with different prices154
786Transpose Graph154
787Total Numbers With no Repeated Digits in a Range154
788Split a String in Balanced Strings Leetcode Solution154
789k-th missing element in increasing sequence which is not present in a given sequence154
790Maximum Difference Between Increasing Elements LeetCode Solution154
791Program for Bridge and Torch problem154
792Linked List Cycle154
793Interval Tree153
794Print a Binary Tree in Vertical Order153
795Minimum Jumps to Reach Home LeetCode Solution153
796Get Maximum in Generated Array Leetcode Solution153
797Sort an array according to the order defined by another array153
798Nearest Exit from Entrance in Maze LeetCode Solution153
799Search in a Binary Search Tree Leetcode Solution153
800One Edit Distance LeetCode Solution153
801Deletion in a Binary Tree153
802Base 7 Leetcode Solution153
803Growable array based stack153
804Last Stone Weight II LeetCode Solution153
805Count quadruples from four sorted arrays whose sum is equal to a given value x153
806N-Queens LeetCode Solution153
807Number of NGEs to the Right153
808Minimum number of jumps to reach end152
809Crawler Log Folder Leetcode Solution152
810A Space Optimized DP solution for 0-1 Knapsack Problem152
811Number Complement Leetcode Solution152
812Merge Sorted Array LeetCode Solution152
813Priority Queue using doubly linked list152
814Relative Ranks Leetcode Solution152
815Check for Palindrome after every character replacement Query152
816Iterative Preorder Traversal152
817Circular Queue152
818Subarray Product Less Than K LeetCode Solution152
819String comparison containing wildcards152
820Minimum swaps to make sequences increasing152
821Reorder Data in Log Files LeetCode Solution152
822Course Schedule II – LeetCode152
823Minimum Time Visiting All Points Leetcode Solution152
824Remove Duplicates from Sorted List LeetCode Solution152
825Maximum Profit in Job Scheduling Leetcode Solution152
826Remove Duplicates from Sorted List II152
827Nested List Weight Sum II LeetCode Solution152
828Maximum size subarray sum equals k151
829Form Minimum Number From Given Sequence151
830Spiral Matrix II Leetcode Solution151
831Sort Array By Parity II Leetcode Solution151
832Find all triplets with zero sum151
833Longest Subarray Having Count of 1s One More than Count of 0s151
834Make Two Arrays Equal by Reversing Sub-arrays Leetcode Solution150
835Insert into a Binary Search Tree Leetcode Solution150
836Can Place Flowers LeetCode Solution150
837Valid Parentheses Leetcode Solution150
838Given an Array of Pairs Find all Symmetric Pairs in it150
839Path with maximum average value150
840Alien Dictionary LeetCode Solution150
841Find the subarray with least average150
842Sum of nearest smaller and greater number150
843Regular Expression Matching150
844Convert BST to Min Heap150
845Brick Wall LeetCode Solution150
846Maximum Nesting Depth of the Parentheses Leetcode Solution150
847Friends Pairing Problem149
848Check whether a given Binary Tree is Complete or not149
849Sort Colors149
850Clone Graph LeetCode Solution149
851Check if a given array can represent Preorder Traversal of Binary Search Tree149
852Permutation Coefficient149
853Level order Traversal in Spiral Form149
854Minimum Number of Taps to Open to Water a Garden LeetCode Solution149
855Partition List Leetcode Solution149
856Count Distinct Elements in Every Window of Size K149
857Count Negative Numbers in a Sorted Matrix LeetCode Solution149
858Find All Possible Recipes from Given Supplies LeetCode Solution149
859Subset with sum divisible by m149
860Subsequence of Size K With the Largest Even Sum LeetCode Solution149
861Top K Frequent Words LeetCode Solution149
862Binary Search Tree Search and Insertion149
863Design a Stack With Increment Operation Leetcode Solution148
864Find Maximum Sum Possible Equal Sum of Three Stacks148
865Range LCM Queries148
866Check if stack elements are pairwise consecutive148
867Tree Traversal (Preorder, Inorder & Postorder)148
868LCS (Longest Common Subsequence) of three strings148
869Sequences of given length where every element is more than or equal to twice of previous148
870An Interesting Method to generate Binary Numbers from 1 to n148
871Matrix Chain Multiplication148
872Guess Number Higher or Lower LeetCode Solution148
873Missing Element in Sorted Array LeetCode Solution148
874Find the Only Repetitive Element Between 1 to N-1148
875Minimum Sum Path in a Triangle148
876Identify and Mark Unmatched Parenthesis in an Expression147
877Water Bottles Leetcode Solution147
878Distinct adjacent elements in an array147
879Best Time to Buy and Sell Stock with Transaction Fee Leetcode Solution147
880Repeated Substring Pattern LeetCode Solution147
881Balanced Expression with Replacement147
882Diagonal Traverse LeetCode Solution147
883Convert Sorted List to Binary Search Tree147
884K’th Largest Element in BST when modification to BST is not allowed147
885Design Browser History LeetCode Solution147
886Sorted Array to Balanced BST147
887Brightest Position on Street LeetCode Solution147
888Diagonal Traversal LeetCode Solution147
889Number of Days Between Two Dates LeetCode Solution147
890Guess Number Higher or Lower II146
891Rearrange an Array Such that arr[i] is equal to i146
892Three way partitioning of an array around a given range146
893Time Based Key-Value Store LeetCode Solution146
894Union and Intersection of two Linked Lists146
895Minimum sum of multiplications of n numbers146
896GCDs of given index ranges in an array146
897Daily Temperatures Leetcode Solution146
898Special Positions in a Binary Matrix Leetcode Solution146
899Insert Delete GetRandom146
900Shortest Word Distance Leetcode Solution146
901BFS for Disconnected Graph146
902Destination City Leetcode Solution146
903Maximum Score After Splitting a String Leetcode Solution146
904Check if an Array is Stack Sortable146
905Count ways to reach the nth stair using step 1, 2 or 3145
906Minimum Swaps to Make Strings Equal Leetcode Solution145
907Rearrange Array such that arr[i] >= arr[j] if i is even and arr[i] <= arr[j] if i is odd and j < i145
908Lemonade Change Leetcode Solution145
909Delete And Earn145
910Least Number of Unique Integers after K Removals Leetcode Solution145
911Range sum queries without updates145
912Find distance between two nodes of a Binary Tree145
913Check if the given array can represent Level Order Traversal of Binary Search Tree145
914Spiral Matrix III LeetCode Solution145
915Find Common Characters Leetcode Solution145
916Robot Bounded In Circle LeetCode Solution145
917Palindrome Partitioning Leetcode Solution144
918Rearrange Spaces Between Words Leetcode Solution144
919Construct BST from its given Level Order Traversal144
920Print Fibonacci sequence using 2 variables144
921Merge Two Sorted Lists Leetcode144
922Queue using Stacks144
923Number of Distinct Islands Leetcode Solution144
924Vertical sum in a given binary tree144
9254Sum144
926Construct Complete Binary Tree from its Linked List Representation144
927Minimum Height Trees LeetCode Solution143
928Maximum Frequency Stack Leetcode Solution143
929Stone Game II Leetcode143
930Alien Dictionary143
9313 Sum143
932Check if any two intervals overlap among a given set of intervals143
933Maximum Subarray Sum Excluding Certain Elements143
934Construct the Rectangle Leetcode Solution143
935A program to check if a binary tree is BST or not143
936Split Array Into Consecutive Subsequences143
937Averages of Levels in Binary Tree143
938Difference Array | Range update query in O(1)142
939Lexicographical Numbers Leetcode Solution142
940Largest area rectangular sub-matrix with equal number of 1’s and 0’s142
941Count Subarrays with Same Even and Odd Elements142
942Strongly Connected Component142
943Queries for GCD of all numbers of an array except elements in a given range142
944Iterative Postorder Traversal Using Two Stacks142
945Create Maximum Number142
946Set Matrix Zeroes Leetcode Solution142
947Binary Tree Longest Consecutive Sequence LeetCode Solution142
948Trim a Binary Search Tree142
949Infix to Postfix142
950Remove Duplicates from Sorted List II LeetCode Solution142
951Longest Palindromic Subsequence142
952Unique Paths II141
953Binary array after M range toggle operations141
954Number of Equivalent Domino Pairs Leetcode Solution141
955Shuffle 2n integers as a1-b1-a2-b2-a3-b3-..bn without using extra space141
956Analyze User Website Visit Pattern LeetCode Solution141
957Find all permuted rows of a given row in a matrix141
958All Unique Triplets that Sum up to a Given Value141
959Sliding Window Maximum141
960Collect maximum points in a grid using two traversals141
961Count Submatrices With All Ones LeetCode Solution141
962Three Consecutive Odds Leetcode Solution140
963Can Make Arithmetic Progression From Sequence Leetcode Solution140
964Dividing Array into Pairs With Sum Divisible by K140
965Minesweeper LeetCode Solution140
966Height of a generic tree from parent array140
967Pattern Occurrences using Stack140
968Merging Intervals140
969Word Break140
970Count subarrays where second highest lie before highest140
971Maximum Product Subarray140
972Intersection of Two Linked Lists LeetCode Solution140
973Reverse Nodes in K-Group140
974Find postorder traversal of BST from preorder traversal140
975Sign of the Product of an Array LeetCode Solution140
976Palindrome Partitioning139
977Find the Difference Leetcode Solution139
978Count Primes in Ranges139
979Newman-Conway Sequence139
980Length of Longest Fibonacci Subsequence139
981The Painter’s Partition Problem139
982Count pair with Given Sum139
983Kth Smallest Element in a BST Leetcode Solution139
984Median of Two Sorted Arrays139
985Product of Array Except Self LeetCode Solution139
986Binary Search Tree Delete Operation139
987Longest Nice Substring LeetCode Solution139
988Level Order Traversal of Binary Tree139
989Symmetric Tree139
990Asteroid Collision LeetCode Solution138
991Segment Tree138
992Find Maximum of Minimum for Every Window Size in a Given Array138
993My Calendar I LeetCode Solution138
994Maximize Sum of Array after K Negations Leetcode Solution138
995K Closest Points to Origin Leetcode Solution138
996Check If a Word Occurs As a Prefix of Any Word in a Sentence Leetcode Solution138
997Climbing stairs138
998Find Duplicate Subtrees137
999Number Of Longest Increasing Subsequence137
1000Merge Sort137
1001Maximum subsequence sum such that no three are consecutive137
1002Double the first element and move zero to end137
1003String Matching in an Array Leetcode Solution137
1004The Maze III LeetCode Solution137
1005Valid Boomerang Leetcode Solution137
1006Largest Number Leetcode Solution137
1007Maximum Product of Indexes of Next Greater on Left and Right137
1008Construction of Longest Increasing Subsequence (N log N)137
1009Compute nCr % p137
1010Breadth First Search (BFS) for a Graph137
1011Depth First Search (DFS) for a Graph137
1012Find the First Circular Tour that visits all the Petrol Pumps137
1013Number of palindromic paths in a matrix137
1014Friends Of Appropriate Ages LeetCode Solution137
1015Largest divisible pairs subset137
1016Maximum Length of Repeated Subarray137
1017Boundary Traversal of binary tree137
1018Shortest Completing Word Leetcode Solution137
1019Morris Inorder Traversal136
1020Serialize and Deserialize Binary Tree136
1021Minimum Index Sum of Two Lists136
1022Graph Valid Tree LeetCode Solution136
1023Next Greater Element III LeetCode Solution136
1024Level order traversal using two Queues136
1025Insertion in a Binary Tree136
1026Largest Substring Between Two Equal Characters Leetcode Solution136
1027Construct Binary Tree from given Parent Array representation136
1028Kill Process LeetCode Solution136
1029Binary Search Tree136
1030Rearrange an array such that ‘arr[j]’ becomes ‘i’ if ‘arr[i]’ is ‘j’136
1031First missing positive136
1032Partition Equal Subset Sum136
1033Maximum Number of Ways to Partition an Array LeetCode Solution136
1034Boolean Parenthesization Problem136
1035Find number of pairs in an array such that their XOR is 0136
1036Maximum weight transformation of a given string136
1037Make The String Great Leetcode Solution136
1038Longest subsequence such that difference between adjacents is one135
1039Design Hit Counter LeetCode Solution135
1040Scramble String LeetCode Solution135
1041Count minimum steps to get the given desired array135
1042Invalid Transactions LeetCode Solution135
1043Advantages of BST over Hash Table135
1044K maximum sums of overlapping contiguous sub-arrays135
1045Build an Array With Stack Operations Leetcode Solution135
1046Decrypt String from Alphabet to Integer Mapping Leetcode Solution135
1047Rearrange array such that even positioned are greater than odd134
1048Path Sum II LeetCode Solution134
1049Available Captures for Rook Leetcode Solution134
1050Ugly Numbers134
1051Balanced Binary Tree134
1052Maximum Sum of 3 Non-Overlapping Subarrays134
1053Custom Sort String Leetcode Solution134
1054Validate Binary Search Tree134
1055Iterative Depth First Traversal of Graph133
1056Defanging an IP Address LeetCode Solution133
1057Super Ugly Number133
1058Implement Trie (Prefix Tree) Leetcode Solution133
1059Bitwise AND of Numbers Range LeetCode Solution133
1060Maximum length subsequence with difference between adjacent elements as either 0 or 1133
1061Ugly Number II LeetCode Solution133
1062Employee Importance LeetCode Solution133
1063Count pairs from two sorted arrays whose sum is equal to a given value x133
1064Kth Smallest Element in a Sorted Matrix LeetCode Solution133
1065Add two numbers133
1066Maximum difference between frequency of two elements such that element having greater frequency is also greater133
1067Lowest Common Ancestor132
1068Populating Next Right Pointers in Each Node Leetcode Solution132
1069Find Peak Element132
1070Recover Binary Search Tree Leetcode Solution132
1071Remove Duplicates from Sorted Array II Leetcode Solution132
1072Move all negative elements to end in order with extra space allowed132
1073Generate Parentheses Leetcode Solution132
1074Regular Expression Matching Regular Expression Matching LeetCode Solution132
1075Search in Sorted Rotated Array132
1076Largest BST Subtree LeetCode Solution131
1077Find a Peak Element II LeetCode Solution131
1078Number of Students Doing Homework at a Given Time Leetcode Solution131
1079Subarrays with K Different Integers Leetcode Solution131
1080Longest Bitonic Subsequence131
1081Binary Tree Right Side View LeetCode Solution131
1082Determine Whether Matrix Can Be Obtained By Rotation LeetCode Solution131
1083Root to Leaf path with target sum Leetcode Solutions131
1084Maximize Distance to Closest Person LeetCode Solution130
1085Clone a Binary Tree with Random Pointers130
1086Day of the Year Leetcode Solution130
1087Number of siblings of a given Node in n-ary Tree130
1088Minimum Size Subarray Sum130
1089Find whether a subarray is in form of a mountain or not130
1090Rearrange array such that even index elements are smaller and odd index elements are greater130
1091Kth Smallest Product of Two Sorted Arrays LeetCode Solution130
1092Number of Closed Islands Leetcode Solution130
1093Smallest Common Region Leetcode Solution130
1094Combination Sum IV LeetCode Solution130
1095Remove Palindromic Subsequences Leetcode Solution129
1096Consecutive Characters LeetCode Solution129
1097Increasing Triplet Subsequence LeetCode Solution129
1098Minimum Absolute Difference in BST Leetcode Solution129
1099Serialize and Deserialize Binary Tree LeetCode Solution129
1100Next Permutation Leetcode Solution129
1101Find maximum difference between nearest left and right smaller elements129
1102Convert BST into a Min-Heap without using array129
1103Level of Each node in a Tree from source node129
1104Count Largest Group Leetcode Solution129
1105Types of Binary Tree129
1106Find the minimum distance between two numbers129
1107Distinct Subsequences129
1108Find Smallest Range Containing Elements from k Lists129
1109Binary Tree Data Structure129
1110Remove duplicates from sorted array128
1111Third Maximum Number Leetcode Solution128
1112Iterative method to find ancestors of a given binary tree128
1113Valid Tic-Tac-Toe State LeetCode Solution128
1114Path Sum128
1115Cutting a Rod128
1116Print all triplets in sorted array that form AP128
1117Find Three Element From Different Three Arrays Such That a + b + c = sum128
1118Construct Binary Tree from Preorder and Postorder Traversal LeetCode Solution128
1119Constant time range add operation on an array128
1120Divisible Pairs Counting128
1121Prime Palindrome LeetCode Solution127
1122Palindrome Permutation LeetCode Solution127
1123Reformat The String Leetcode Solution127
1124Sum of Even Numbers After Queries127
1125Print Next Greater Number of Q queries127
1126Products of ranges in an array127
1127Longest Subarray of 1’s After Deleting One Element LeetCode Solution127
1128Maximum Product Subarray127
1129Print Right View of a Binary Tree126
1130Search Insert Position126
1131Minimum Score Triangulation of Polygon Leetcode Solution126
1132Thousand Separator Leetcode Solution126
1133Cells with Odd Values in a Matrix LeetCode Solution126
1134Delete Nodes and Return Forest Leetcode Solution126
1135Bottom View of a Binary Tree126
1136Mean of Array After Removing Some Elements Leetcode Solution126
1137Longest Increasing Consecutive Subsequence126
1138Write Code to Determine if Two Trees are Identical126
1139Topological Sorting125
1140Search an Element in Sorted Rotated Array125
1141Minimum sum of squares of character counts in a given string after removing k characters125
1142Palindromic Substrings Leetcode Solution125
1143Construct K Palindrome Strings LeetCode Solution125
1144Merge two BSTs with limited extra space125
1145Moser-de Bruijn Sequence125
1146Swap Nodes In Pairs124
1147Priority Queue124
1148Maximum Binary Tree124
1149Subset Sum Problem in O(sum) space124
1150Closest Binary Search Tree Value Leetcode Solution124
1151Maximum Product of Splitted Binary Tree LeetCode Solution124
1152Find Two Non-overlapping Sub-arrays Each With Target Sum LeetCode Solution124
1153Red-Black Tree Introduction124
1154Find maximum length Snake sequence124
1155Check Array Formation Through Concatenation Leetcode Solution123
1156Print modified array after executing the commands of addition and subtraction123
1157Bus Routes Leetcode Solution123
1158Golomb sequence123
1159Diameter of N-Ary Tree LeetCode Solution123
1160Possible Bipartition LeetCode Solution123
1161Transform a BST to Greater sum Tree122
1162Kth Smallest Number in Multiplication Table Leetcode Solution122
1163Maximize sum of consecutive differences in a circular array122
1164Binary Tree to Binary Search Tree Conversion122
1165Web Crawler LeetCode Solution122
1166Find Largest Value in Each Tree Row LeetCode Solution122
1167Rotate Array122
1168Minimum Sideway Jumps LeetCode Solution122
1169Search Suggestions System LeetCode Solution122
1170Find a sorted subsequence of size 3 in linear time122
1171Queries for Number of Distinct Elements in a Subarray122
1172Remove Max Number of Edges to Keep Graph Fully Traversable Leetcode Solution122
1173Compare Strings by Frequency of the Smallest Character Leetcode Solution121
1174Decision Tree121
1175Count even length binary sequences with same sum of first and second half bits121
1176Graph and its representation121
1177Minimum Cost to Move Chips to The Same Position LeetCode Solution121
1178Matchsticks to Square Leetcode Solution121
1179Longest Repeated Subsequence121
1180Find the smallest binary digit multiple of given number121
1181Contiguous Array LeetCode Solution120
1182Lowest Common Ancestor in Binary Search Tree120
1183Factorial Trailing Zeroes LeetCode Solution120
1184Convert Sorted Array to Binary Search Tree LeetCode Solutions120
1185First Bad Version120
1186Swapping Nodes in a Linked List Leetcode Solution120
1187Sum of Left Leaves LeetCode Solution119
1188K’th Largest element in BST using constant extra space119
1189Maximum sum bitonic subarray119
1190Number of Orders in the Backlog Leetcode Solution119
1191Decrease Elements To Make Array Zigzag LeetCode Solution119
1192Reverse a Path in BST using Queue119
1193Queue Reconstruction by Height119
1194Valid Triangle Number119
1195Minimum Moves to Equal Array Elements LeetCode Solution119
1196Maximum number of segments of lengths a, b and c118
1197How to print maximum number of A’s using given four keys118
1198Reformat Date LeetCode Solution118
1199Maximum sum of pairs with specific difference118
1200Count Pairs Whose Products Exist in Array118
1201Lowest Common Ancestor of a Binary Tree Leetcode Solution118
1202Given a binary tree, how do you remove all the half nodes?118
1203Closest Leaf in a Binary Tree LeetCode Solution118
1204Range Queries for Longest Correct Bracket Subsequence118
1205Moving Stones Until Consecutive Leetcode Solution118
1206Array Queries for multiply replacements and product117
1207Kth Smallest Element in a BST117
1208Guess The Word117
1209Champagne Tower LeetCode Solution117
1210Path Crossing Leetcode Solution116
1211Replace two consecutive equal values with one greater116
1212Concatenation of Array LeetCode Solution116
1213Filter Restaurants by Vegan-Friendly, Price and Distance Leetcode Solution116
1214Minimum Swaps To Make Sequences Increasing LeetCode Solution116
1215Convert Integer to the Sum of Two No-Zero Integers Leetcode Solution116
1216Valid Perfect Square LeetCode Solution115
1217Range Sum Query using Sparse Table115
1218Integer Break LeetCode Solution115
1219Arithmetic Slices II – Subsequence LeetCode Solution115
1220Flatten 2D Vector LeetCode Solution115
1221Perfect Squares LeetCode Solution115
1222Write a function to get the intersection point of two Linked Lists115
1223Maximum sum of a path in a Right Number Triangle114
1224Maximum Depth Of Binary Tree114
1225BST to a Tree with Sum of all Smaller Keys114
1226Check if each internal node of a BST has exactly one child114
1227Power of Two114
1228New 21 Game114
1229Design Skiplist LeetCode Solution114
1230Check Completeness of a Binary Tree LeetCode Solution114
1231Divide Two Integers Leetcode Solution114
1232Sliding Window Median Leetcode Solution114
1233The kth Factor of n Leetcode Solution114
1234LRU Cache Leetcode Solution114
1235Mean of range in array114
1236Largest Plus Sign Leetcode Solution113
1237Queries on Probability of Even or Odd Number in given Ranges113
1238Maximum Value at a Given Index in a Bounded Array LeetCode Solution113
1239Maximize Elements Using Another Array113
1240Contiguous Array113
1241Print modified array after multiple array range increment operations113
1242Longest Common Prefix Using Word by Word Matching113
1243Check if all levels of two Binary Tree are anagrams or not113
1244Check for Identical BSTs without building the trees113
1245Bold Words in String LeetCode Solution113
1246Find Minimum in Rotated Sorted Array II LeetCode Solution113
1247Parallel Courses II LeetCode Solution112
1248Print Ancestors of a Given Binary Tree Node Without Recursion112
1249Print n terms of Newman-Conway Sequence112
1250Maximum Array from Two given Arrays Keeping Order Same112
1251Find k-th smallest element in BST (Order Statistics in BST)112
1252Count Subsets Having Distinct Even Numbers111
1253Graph Cloning111
1254Find minimum number of merge operations to make an array palindrome111
1255Merge k Sorted Lists Leetcode Solution111
1256Symmetric Tree LeetCode Solution Leetcode Solution111
1257Maximum Product Subarray111
1258Missing Number110
1259Smallest Range II Leetcode Solution110
1260Count and Toggle Queries on a Binary Array110
1261Check if two nodes are on the same path in a Tree110
1262Minimum Remove to Make Valid Parentheses LeetCode Solution110
1263Verify Preorder Serialization of a Binary Tree109
1264Number of elements less than or equal to a given number in a given subarray109
1265Next greater element109
1266Image Overlap LeetCode Solution108
1267Excel Sheet Column Title LeetCode Solution108
1268Minimum Time to Collect All Apples in a Tree LeetCode Solution108
1269Check If a String Can Break Another String Leetcode Solution108
1270Orderly Queue LeetCode Solution107
1271Palindrome Partitioning107
1272Min Cost Climbing Stairs LeetCode Solution107
1273Different Ways to Add Parentheses Leetcode Solution107
1274Koko Eating Bananas LeetCode Solution107
1275Peeking Iterator LeetCode Solution105
1276Check if X can give change to every person in the Queue105
1277Newman–Shanks–Williams prime105
1278Longest Substring Without Repeating Characters Leetcode Solution105
1279Largest Submatrix With Rearrangements LeetCode Solution105
1280Check in binary array the number represented by a subarray is odd or even104
1281Merge Sorted Array103
1282Range Minimum Query (Square Root Decomposition and Sparse Table)103
1283Array Nesting Leetcode Solution102
1284Arranging Coins Leetcode Solution101
1285Maximum Sum Increasing Subsequence101
1286Find maximum average subarray of k length100
1287Encoded String With Shortest Length LeetCode Solution100
1288Maximum product of an increasing subsequence100
1289Number of indexes with equal elements in given range99
1290Queries for Decimal Values of Subarrays of a Binary Array99
1291Minimum Total Space Wasted With K Resizing Operations LeetCode Solution99
1292Minimum Number of People to Teach LeetCode Solution98
1293Convert to Base -2 LeetCode Solution98
1294Reach a Number LeetCode Solution97
1295Convert a BST to a Binary Tree such that sum of all greater keys is added to every key97
1296Random Pick Index LeetCode Solution97
1297Add Two Numbers II Leetcode Solution96
1298Check given array of size n can represent BST of n levels or not96
1299Vertical Order Traversal of Binary Tree LeetCode Solution96
1300Find the Winner of the Circular Game LeetCode Solution96
1301Binary Tree to Binary Search Tree Conversion using STL set96
1302Continuous Subarray Sum LeetCode Solution96
1303Palindrome Number LeetCode Solution95
1304Queries on XOR of greatest odd divisor of the range95
1305Number of Subsequences That Satisfy the Given Sum Condition LeetCode solution95
1306Jump Game IV LeetCode Solution95
1307Insert Delete GetRandom O(1) Leetcode Solution94
1308Minimum Possible Integer After at Most K Adjacent Swaps On Digits LeetCode Solution94
1309Design Underground System Leetcode Solution90
1310Print Maximum Length Chain of Pairs89
1311Detect Capital Leetcode Solution87
1312Design A Leaderboard Leetcode Solution86
1313Top K Frequent Elements LeetCode Solution83
1314Minimum Swaps to Group All 1’s Together Leetcode Solution83
1315Substring with Concatenation of All Words Leetcode Solution83
1316Binary Tree Inorder Traversal LeetCode Solution81
1317Minimum Path Sum Leetcode Solution80
1318Count Sub Islands LeetCode Solution80
1319Shifting Letters LeetCode Solution79
1320Longest Common Subsequence LeetCode Solution77
1321Odd Even Linked List Leetcode Solution77
1322Find the Town Judge LeetCode Solution76
1323Best Meeting Point LeetCode Solution76
1324Decode String Leetcode Solution76
1325Find the Town Judge LeetCode Solution75
1326Maximum Population Year LeetCode Solution75
1327Shortest Unsorted Continuous Subarray LeetCode Solution72
1328Sum Root to Leaf Numbers LeetCode Solution72
1329Rectangle Overlap LeetCode Solution71
1330Maximum Population Year LeetCode Solution71
1331Design Add and Search Words Data Structure LeetCode Solution70
1332Score of Parenthesis LeetCode Solution67
1333Flatten Binary Tree to Linked List LeetCode Solution67
1334Stone Game IV LeetCode Solution67
1335Range Sum Query 2D – Immutable LeetCode Solution66
1336Insert into a Sorted Circular Linked List LeetCode Solution66
1337Reveal Cards In Increasing Order Leetcode Solution63
1338Valid Triangle Number LeetCode Solution62
1339Is Graph Bipartite? LeetCode Solution62
1340Divide Chocolate LeetCode Solution55
1341Step-By-Step Directions From a Binary Tree Node to Another LeetCode Solution48
1342Reverse Integer Leetcode Solution46
1343Range Sum of BST LeetCode Solution45
1344Sort Colors LeetCode Solution42
1345Find K Closest Elements LeetCode Solution40
1346Maximum Side Length of a Square with Sum Less than or Equal to Threshold LeetCode Solution38
1347Excel Sheet Column Number LeetCode Solution37
1348Rotate String LeetCode Solution37
1349H-Index Leetcode Solution20
1350Maximum Size Subarray Sum Equals k Leetcode Solution20
1351High Five LeetCode Solution19
1352Insert Delete GetRandom O(1) – Duplicates allowed LeetCode Solution10
1353Unique Binary Search Trees LeetCode Solution10
1354Monotonic Array Leetcode Solution10
1355Valid Triangle Number LeetCode Solution7
1356Swim in Rising Water LeetCode Solution6
1357Peak Index in a Mountain Array LeetCode Solution
Translate »