Top K Frequent Elements LeetCode Solution

Difficulty Level Medium
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Problem Statement

Top K Frequent Elements LeetCode Solution Says that – Given an integer array nums and an integer k, return the k most frequent elements. You may return the answer in any order.

Example 1:

Input:

 nums = [1,1,1,2,2,3], k = 2

Output:

 [1,2]

Example 2:

Input:

 nums = [1], k = 1

Output:

 [1]

 

Constraints:

  • 1 <= nums.length <= 105
  • k is in the range [1, the number of unique elements in the array].
  • It is guaranteed that the answer is unique.

 

Algorithm:

Idea:

  • In order to find the Top k Frequent Elements. First, we will focus on the frequency of each element present in an array.
  • After finding the Frequency of Each element we will make one maximum heap and push all elements into the heap with their Frequency.
  • At last, we will make one result list and will pop out the k element from the heap and append that element into the result and return the result.

Approach:

  • At first, We will make one Hashmap and will traverse through the whole array and set the frequency of each element as value and element as Key in the Hashmap.
  • After that, we will make one priority queue(maxheap) and again traverse through the whole array and push all the elements as tuple pairs (-value, key) into the maxheap.
  • Then, we will run a loop from 0 to K and pop out the elements from maxheap and append the Key of each tuple into the result and return the result.
  • Hence We will find the Top K frequent Elements.

Top K Frequent Elements LeetCode SolutionPin

class Solution:
    def topKFrequent(self, nums: List[int], k: int) -> List[int]:
        dic = {}
        
        for i in nums:
            if i in dic:
                dic[i] += 1
                
            else:
                dic[i] = 1
        
        max_heap = []
        for i in dic:
            heapq.heappush(max_heap,(-dic[i],i))
            
        result = []
        for i in range(k):
            result.append(heapq.heappop(max_heap)[1])
        
        return result
        
            
        
        
class Solution {
    public int[] topKFrequent(int[] nums, int k) {
        
      Map<Integer, Integer> dic = new HashMap<>();
        for(int num : nums){ dic.put(num, dic.getOrDefault(num, 0) + 1); }
        
        Queue<Integer> max_heap = new PriorityQueue<>((a, b) -> dic.get(b) - dic.get(a));
        for(int key : dic.keySet()){ max_heap.add(key); }
        
        int[] result = new int[k];
        for(int i = 0; i < k; i++){
            result[i] = max_heap.poll();
        }
        
        return result;
    } 
}

Complexity Analysis of Top K Frequent Elements Leetcode Solution:

Time complexity:

The Time Complexity of the above solution is O(nlogn) where n = the size of the input array. We have traversed the entire array and for each element, we are doing the heapify operation.

Space complexity:

The Space Complexity of the above solution is O(n) since we are creating a max heap of size n.

SIMILAR QUESTION                 https://leetcode.com/problems/word-frequency/

https://leetcode.com/problems/kth-largest-element-in-an-array/

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577The Knapsack Problem169
578Gold Mine Problem169
579Insert Interval Leetcode Solution169
580Find the smallest positive integer value that cannot be represented as sum of any subset of a given array168
581Group Multiple Occurrence of Array Elements Ordered by first Occurrence168
582Maximum path sum in a triangle168
583Change the Array into Permutation of Numbers From 1 to N168
584Summary Ranges Leetcode Solution168
585Shortest Path in a Grid with Obstacles Elimination LeetCode Solution168
5863Sum Closest LeetCode Solution168
587Check for Balanced Parentheses in an Expression168
588Minimum Knight Moves LeetCode Solution168
589Unique Binary Search Trees167
590XOR Operation in an Array Leetcode Solution167
591Decode Ways167
592Rotate List Leetcode Solution167
593Minimum number of distinct elements after removing m items167
594K Empty Slots LeetCode167
595Distance Between Bus Stops Leetcode Solution166
596Combinations Leetcode Solution166
597Rotate Image LeetCode Solution166
598Same Tree LeetCode Solution166
599How to check if two given sets are disjoint?166
600Sieve of Eratosthenes166
601LRU Cache LeetCode Solution166
602Permutation in String Leetcode Solution165
603Frog Jump Leetcode Solution165
604Sort Characters By Frequency LeetCode Solution165
605Find minimum difference between any two elements165
606Remove All Occurrences of a Substring LeetCode Solution165
607Maximum difference between first and last indexes of an element in array165
608Best Time to Buy and Sell Stock LeetCode Solution164
609Stone Game LeetCode164
610Replace Elements with Greatest Element on Right Side Leetcode Solution164
611Segregate 0s and 1s in an Array164
612Maximum Distance in Array164
613Find Sum of all unique sub-array sum for a given array164
614Painting Fence Algorithm164
615License Key Formatting Leetcode Solution164
616Printing brackets in Matrix Chain Multiplication Problem164
617Minimum number of subsets with distinct elements164
618Word Pattern164
619Smallest Good Base163
620Sort Array By Parity LeetCode Solution163
621Minimum insertions to form a palindrome with permutations allowed163
622Find if an Expression has Duplicate Parenthesis or Not163
623Minimum Depth of Binary Tree Leetcode Solution163
624Word Wrap Problem163
625Coin Change Problem162
626Applications of Breadth First Search and Depth First Search162
627Maximum Number of Chocolates to be Distributed Equally Among k Students162
628Defanging an IP Address Leetcode Solution162
629Find the Duplicate Number LeetCode Solution162
630Distance of nearest cell having 1 in a binary matrix162
631Valid Palindrome II Leetcode Solution161
632Kth Missing Positive Number Leetcode Solution161
633Minimum Cost to Hire K Workers161
634House Robber161
635Rearrange an array in order – smallest, largest, 2nd smallest, 2nd largest161
636Tracking current Maximum Element in a Stack161
637Sum of All Odd Length Subarrays Leetcode Solution160
638Binary Tree Zigzag Level Order Traversal LeetCode Solution160
639Optimal Account Balancing LeetCode Solution160
640Find Maximum Level sum in Binary Tree160
641Maximum Consecutive Numbers Present in an Array160
642Longest Substring with At Most K Distinct Characters LeetCode Solution160
643Longest Increasing Subsequence160
644Minimum Number of Steps to Make Two Strings Anagram Leetcode Solutions160
645Iterative Method to find Height of Binary Tree160
646Power of Four Leetcode Solution160
647Non-overlapping sum of two sets160
648Isomorphic Strings160
649Count Good Nodes in Binary Tree Leetcode Solution160
650Merge Two Balanced Binary Search Trees159
651K Empty Slots159
652Reverse a stack without using extra space in O(n)159
653GCD Of Two Numbers159
654Delete consecutive same words in a sequence159
655Moving Average from Data Stream Leetcode Solution159
656Best Time to Buy and Sell Stock with Cooldown Leetcode Solution159
657Check If It Is a Straight Line Leetcode Solution159
658Number of Provinces Leetcode Solution159
659Convert an array to reduced form158
660Maximum Number of Coins You Can Get Leetcode Solution158
661String to Integer (atoi) LeetCode Solution158
662Strobogrammatic Number LeetCode Solution158
663Queries for counts of array elements with values in given range158
664Largest Sum Contiguous Subarray158
665Check If Two String Arrays are Equivalent Leetcode Solution158
666Letter Combinations of a Phone Number158
667Ugly Number Leetcode Solution158
668Wiggle Sort158
669Increasing Decreasing String Leetcode Solution157
670Employee Free Time LeetCode Solution157
671Longest Increasing Path in a Matrix LeetCode Solution157
672Check if a queue can be sorted into another queue using a stack157
673Subset Sum Leetcode157
674Number of Dice Rolls With Target Sum LeetCode Solution157
675Reverse Only Letters LeetCode Solution157
676Find Largest d in Array such that a + b + c = d157
677How to Create Mergable Stack?157
678Sum of f(a[i], a[j]) over all pairs in an array of n integers157
679Print the Fibonacci numbers in reverse order157
680Lucky Numbers in a Matrix Leetcode Solution157
681Flipping an Image LeetCode Solution157
682Reducing Dishes LeetCode Solution157
683Longest Substring with At Least K Repeating Characters LeetCode Solution157
684Partition Labels LeetCode Solution157
685Find the Smallest Divisor given a Threshold Leetcode Solution157
686Reorganize String157
687Find whether an array is subset of another array156
688Reversing a Queue using Recursion156
689Form minimum number from given sequence156
690Valid Perfect Square Leetcode Solution156
691Inorder Successor of a node in Binary Tree156
692Valid Palindrome156
693Path With Maximum Minimum Value LeetCode Solution156
694Unique Paths II Leetcode Solution156
695Find Leaves of Binary Tree LeetCode Solution156
696Maximum Number of Occurrences of a Substring Leetcode Solution156
697Find the Distance Value Between Two Arrays Leetcode Solution156
698Construct BST from given Preorder Traversal155
699Populating Next Right Pointers in Each Node155
700Reservoir Sampling155
701To Lower Case Leetcode Solution155
702Robot Room Cleaner Leetcode Solution155
703Binary Tree zigzag level order Traversal155
704Recover Binary Search Tree155
705Partition Array Into Three Parts With Equal Sum Leetcode Solution155
706Merge Two Binary Trees LeetCode Solution155
707BFS vs DFS for Binary Tree155
708Delete Nth node from the end of the given linked list155
709Permutation Sequence LeetCode Solution155
710Dynamic Programming Basics154
711Sort Array by Increasing Frequency Leetcode Solution154
712Maximum Product of Two Elements in an Array Leetcode Solution154
713Edit Distance LeetCode Solution154
714Maximum Product of Three Numbers LeetCode Solution154
715Majority Element II Leetcode Solution154
716Add and Search Word – Data structure design LeetCode154
717Find pairs with given sum such that elements of pair are in different rows154
718Hamming Distance Leetcode Solution154
719Rank Transform of an Array Leetcode Solution154
720Find the node with minimum value in a Binary Search Tree153
721Numbers with prime frequencies greater than or equal to k153
722Restore IP Addresses Leetcode Solution153
723Keyboard Row Leetcode Solution153
724Remove Invalid Parentheses Leetcode Solution153
725Factorial Trailing Zeroes Leetcode Solution153
726Decompress Run-Length Encoded List Leetcode Solution153
727Convert a Number to Hexadecimal Leetcode Solution153
728Deletion in a Binary Tree152
729Bulb Switcher LeetCode Solution152
730Queue based approach for first non-repeating character in a stream152
731String Compression LeetCode Solution152
732Stack Permutations (Check if an array is stack permutation of other)152
733Longest Span with same Sum in two Binary arrays152
734Minimum Distance Between BST Nodes Leetcode Solution151
735Largest subarray with equal number of 0s and 1s151
736Find unique character in a string151
737Find Maximum Depth of Nested Parenthesis in a String151
738Find All Duplicates in an Array LeetCode Solution151
739Linked List Cycle151
740Race Car LeetCode Solution151
741Find the largest multiple of 3151
742Minimum Height Trees151
743Non-decreasing Array LeetCode Solution151
744Symmetric Tree Leetcode Solution151
745Remove Duplicates from Sorted List LeetCode Solution150
746Find Pair with Greatest Product in Array150
747Bubble sort using two Stacks150
748Minimum Cost For Tickets Leetcode Solution150
749First Unique Character in a String LeetCode Solution150
750Word Pattern LeetCode Solution150
751Maximum Length of a Concatenated String with Unique Characters Leetcode Solution150
752Perform String Shifts Leetcode150
753Search in a Binary Search Tree Leetcode Solution150
754k-th missing element in increasing sequence which is not present in a given sequence150
755Invert Binary Tree LeetCode Solution150
756Maximum 69 Number Leetcode Solution150
757Minimize Maximum Pair Sum in Array LeetCode Solution150
758Sorted Linked List to Balanced BST150
759Binomial Coefficient150
760Generate all possible sorted arrays from alternate elements of two given sorted arrays150
761Binary Tree Maximum Path Sum LeetCode Solution150
762Find if Path Exists in Graph Leetcode Solution150
763Remove Nth Node From End of List Leetcode Solution150
764Merge K Sorted Linked Lists149
765Jump Game149
766Maximum Difference Between Increasing Elements LeetCode Solution149
767Count quadruples from four sorted arrays whose sum is equal to a given value x149
768Morris Traversal149
769Diagonal Traversal of Binary Tree149
770Kth ancestor of a node in binary tree149
771Student Attendance Record I Leetcode Solution149
772Finding K closest element149
773N-Queens LeetCode Solution149
774Evaluate Reverse Polish Notation LeetCode Solution149
775Elements to be added so that all elements of a range are present in array149
776Best Meeting Point LeetCode Solution149
777Find Median from Data Stream LeetCode Solution149
778Number of Islands II LeetCode Solution149
779Growable array based stack149
780Program for Bridge and Torch problem148
781Minimum Time Visiting All Points Leetcode Solution148
782Snakes and Ladders LeetCode Solution148
783Number Complement Leetcode Solution148
784Split a String in Balanced Strings Leetcode Solution148
785Valid Number148
786Largest rectangular sub-matrix whose sum is 0148
787Search a 2D Matrix II Leetcode Solution148
788Remove brackets from an algebraic string containing + and – operators148
789Minimum time required to rot all oranges148
790Nested List Weight Sum II LeetCode Solution147
791Minimum number of jumps to reach end147
792Transpose Graph147
793Largest Rectangle in Histogram LeetCode Solution147
794Special Array With X Elements Greater Than or Equal X Leetcode Solution147
795Remove Duplicates from Sorted List II147
796Nearest Exit from Entrance in Maze LeetCode Solution147
797Merge Sorted Array LeetCode Solution147
798Sort an array according to the order defined by another array147
799Number of NGEs to the Right147
800Maximum Depth of N-ary Tree Leetcode Solution147
801Get Maximum in Generated Array Leetcode Solution147
802Check for Palindrome after every character replacement Query147
803Relative Ranks Leetcode Solution147
804Longest Subarray Having Count of 1s One More than Count of 0s146
805Crawler Log Folder Leetcode Solution146
806Check If Array Pairs Are Divisible by k LeetCode Solution146
807Sort Array By Parity II Leetcode Solution146
808Base 7 Leetcode Solution146
809Print a Binary Tree in Vertical Order146
810Sort Colors146
811Circular Queue146
812String comparison containing wildcards146
813One Edit Distance LeetCode Solution146
814A Space Optimized DP solution for 0-1 Knapsack Problem146
815Final Prices With a Special Discount in a Shop Leetcode Solution146
816Partition to K Equal Sum Subsets Leetcode Solution146
817Minimum Number of Taps to Open to Water a Garden LeetCode Solution146
818Count items common to both the lists but with different prices146
819Convert BST to Min Heap146
820Friends Pairing Problem146
821Tiling Problem146
822Interval Tree145
823Minimum swaps to make sequences increasing145
824Alien Dictionary LeetCode Solution145
825Check if Two Expressions With Brackets are Same145
826Reorder Data in Log Files LeetCode Solution145
827Subsequence of Size K With the Largest Even Sum LeetCode Solution145
828Sorted Array to Balanced BST145
829Subarray Product Less Than K LeetCode Solution145
830Path with maximum average value145
831Clone Graph LeetCode Solution145
832Total Numbers With no Repeated Digits in a Range144
833Minimum Swaps to Make Strings Equal Leetcode Solution144
834Level order Traversal in Spiral Form144
835Make Two Arrays Equal by Reversing Sub-arrays Leetcode Solution144
836Guess Number Higher or Lower LeetCode Solution144
837Partition List Leetcode Solution144
838Priority Queue using doubly linked list144
839Regular Expression Matching144
840Last Stone Weight II LeetCode Solution144
841Maximum Profit in Job Scheduling Leetcode Solution144
842Find the subarray with least average144
843Maximum size subarray sum equals k144
844Design a Stack With Increment Operation Leetcode Solution144
845Iterative Preorder Traversal144
846Course Schedule II – LeetCode144
847Insert into a Binary Search Tree Leetcode Solution144
848Minimum Jumps to Reach Home LeetCode Solution144
849Brightest Position on Street LeetCode Solution143
850Find the Only Repetitive Element Between 1 to N-1143
851Can Place Flowers LeetCode Solution143
852Permutation Coefficient143
853Subset with sum divisible by m143
854Find all triplets with zero sum143
855Union and Intersection of two Linked Lists143
856Check if a given array can represent Preorder Traversal of Binary Search Tree143
857Minimum Sum Path in a Triangle143
858Count Distinct Elements in Every Window of Size K143
859Top K Frequent Words LeetCode Solution143
860Water Bottles Leetcode Solution142
861Given an Array of Pairs Find all Symmetric Pairs in it142
862Find All Possible Recipes from Given Supplies LeetCode Solution142
863Maximum Nesting Depth of the Parentheses Leetcode Solution142
864Check whether a given Binary Tree is Complete or not142
865Brick Wall LeetCode Solution142
866Valid Parentheses Leetcode Solution142
867Three way partitioning of an array around a given range142
868Count ways to reach the nth stair using step 1, 2 or 3141
869LCS (Longest Common Subsequence) of three strings141
870Form Minimum Number From Given Sequence141
871Sum of nearest smaller and greater number141
872Rearrange Spaces Between Words Leetcode Solution141
873Binary Search Tree Search and Insertion141
874Design Browser History LeetCode Solution141
875Check if an Array is Stack Sortable141
876Lemonade Change Leetcode Solution141
8774Sum141
878Matrix Chain Multiplication141
879Spiral Matrix II Leetcode Solution141
880Tree Traversal (Preorder, Inorder & Postorder)141
881Daily Temperatures Leetcode Solution141
882Least Number of Unique Integers after K Removals Leetcode Solution141
883Range sum queries without updates141
884Repeated Substring Pattern LeetCode Solution141
885Construct Complete Binary Tree from its Linked List Representation140
886Count Negative Numbers in a Sorted Matrix LeetCode Solution140
887Find all permuted rows of a given row in a matrix140
888GCDs of given index ranges in an array140
889Shortest Word Distance Leetcode Solution140
890Count Subarrays with Same Even and Odd Elements140
891Insert Delete GetRandom140
892Delete And Earn140
893Destination City Leetcode Solution140
894An Interesting Method to generate Binary Numbers from 1 to n140
895Maximum Score After Splitting a String Leetcode Solution140
896Distinct adjacent elements in an array140
897Best Time to Buy and Sell Stock with Transaction Fee Leetcode Solution140
898Guess Number Higher or Lower II140
899Rearrange an Array Such that arr[i] is equal to i139
900A program to check if a binary tree is BST or not139
901Balanced Expression with Replacement139
902Diagonal Traversal LeetCode Solution139
903Find Maximum Sum Possible Equal Sum of Three Stacks139
904Identify and Mark Unmatched Parenthesis in an Expression139
905Number of Days Between Two Dates LeetCode Solution139
906Convert Sorted List to Binary Search Tree139
907Set Matrix Zeroes Leetcode Solution139
908Queries for GCD of all numbers of an array except elements in a given range139
909Sequences of given length where every element is more than or equal to twice of previous139
910Check if stack elements are pairwise consecutive139
911Missing Element in Sorted Array LeetCode Solution139
912Robot Bounded In Circle LeetCode Solution139
913Time Based Key-Value Store LeetCode Solution138
914Alien Dictionary138
915Range LCM Queries138
916Special Positions in a Binary Matrix Leetcode Solution138
917Find distance between two nodes of a Binary Tree138
918BFS for Disconnected Graph138
919Minimum sum of multiplications of n numbers138
920Diagonal Traverse LeetCode Solution138
921Palindrome Partitioning Leetcode Solution138
922Vertical sum in a given binary tree138
923Check if the given array can represent Level Order Traversal of Binary Search Tree138
924Find Common Characters Leetcode Solution138
925Spiral Matrix III LeetCode Solution137
926Merge Two Sorted Lists Leetcode137
927Merging Intervals137
928Rearrange Array such that arr[i] >= arr[j] if i is even and arr[i] <= arr[j] if i is odd and j < i137
929Stone Game II Leetcode137
930Number of Distinct Islands Leetcode Solution137
931Longest Palindromic Subsequence137
932Remove Duplicates from Sorted List II LeetCode Solution137
933Analyze User Website Visit Pattern LeetCode Solution136
934Maximum Subarray Sum Excluding Certain Elements136
935Number of Equivalent Domino Pairs Leetcode Solution136
936Can Make Arithmetic Progression From Sequence Leetcode Solution136
937K’th Largest Element in BST when modification to BST is not allowed136
938Infix to Postfix136
939Construct the Rectangle Leetcode Solution136
940Lexicographical Numbers Leetcode Solution136
941Sliding Window Maximum136
942Maximum Frequency Stack Leetcode Solution136
943Maximize Sum of Array after K Negations Leetcode Solution136
944Print Fibonacci sequence using 2 variables136
945Queue using Stacks136
946Averages of Levels in Binary Tree136
9473 Sum136
948Intersection of Two Linked Lists LeetCode Solution136
949Largest area rectangular sub-matrix with equal number of 1’s and 0’s135
950Binary array after M range toggle operations135
951Construct BST from its given Level Order Traversal135
952Trim a Binary Search Tree135
953Count Submatrices With All Ones LeetCode Solution135
954Three Consecutive Odds Leetcode Solution135
955Minimum Height Trees LeetCode Solution135
956Median of Two Sorted Arrays135
957Difference Array | Range update query in O(1)135
958Breadth First Search (BFS) for a Graph135
959All Unique Triplets that Sum up to a Given Value135
960Binary Tree Longest Consecutive Sequence LeetCode Solution135
961Pattern Occurrences using Stack135
962Dividing Array into Pairs With Sum Divisible by K135
963Largest divisible pairs subset134
964Check if any two intervals overlap among a given set of intervals134
965Largest Substring Between Two Equal Characters Leetcode Solution134
966Find postorder traversal of BST from preorder traversal134
967Word Break134
968Strongly Connected Component134
969Newman-Conway Sequence134
970Palindrome Partitioning134
971Height of a generic tree from parent array134
972Check If a Word Occurs As a Prefix of Any Word in a Sentence Leetcode Solution134
973Find Maximum of Minimum for Every Window Size in a Given Array134
974Depth First Search (DFS) for a Graph133
975Shuffle 2n integers as a1-b1-a2-b2-a3-b3-..bn without using extra space133
976Symmetric Tree133
977Maximum Product Subarray133
978Kth Smallest Element in a BST Leetcode Solution133
979Create Maximum Number133
980Segment Tree133
981Binary Search Tree Delete Operation133
982First missing positive133
983Reverse Nodes in K-Group133
984Product of Array Except Self LeetCode Solution133
985Iterative Postorder Traversal Using Two Stacks133
986Split Array Into Consecutive Subsequences133
987Length of Longest Fibonacci Subsequence132
988Find Duplicate Subtrees132
989My Calendar I LeetCode Solution132
990Level Order Traversal of Binary Tree132
991Climbing stairs132
992Count pair with Given Sum132
993Asteroid Collision LeetCode Solution132
994The Maze III LeetCode Solution132
995Minesweeper LeetCode Solution132
996Boundary Traversal of binary tree132
997Count Primes in Ranges132
998Sign of the Product of an Array LeetCode Solution132
999Maximum subsequence sum such that no three are consecutive132
1000Rearrange array such that even positioned are greater than odd132
1001Find the Difference Leetcode Solution131
1002Longest Nice Substring LeetCode Solution131
1003Maximum Number of Ways to Partition an Array LeetCode Solution131
1004Longest subsequence such that difference between adjacents is one131
1005Decrypt String from Alphabet to Integer Mapping Leetcode Solution131
1006Double the first element and move zero to end131
1007Kill Process LeetCode Solution131
1008Make The String Great Leetcode Solution131
1009Serialize and Deserialize Binary Tree131
1010Partition Equal Subset Sum131
1011Find the First Circular Tour that visits all the Petrol Pumps131
1012Maximum Length of Repeated Subarray130
1013Valid Boomerang Leetcode Solution130
1014Insertion in a Binary Tree130
1015Largest Number Leetcode Solution130
1016Shortest Completing Word Leetcode Solution130
1017Graph Valid Tree LeetCode Solution130
1018The Painter’s Partition Problem130
1019Level order traversal using two Queues130
1020Super Ugly Number130
1021Next Greater Element III LeetCode Solution130
1022Unique Paths II130
1023Find number of pairs in an array such that their XOR is 0130
1024Count subarrays where second highest lie before highest129
1025Compute nCr % p129
1026K Closest Points to Origin Leetcode Solution129
1027Number Of Longest Increasing Subsequence129
1028Design Hit Counter LeetCode Solution129
1029Friends Of Appropriate Ages LeetCode Solution129
1030Collect maximum points in a grid using two traversals129
1031Ugly Number II LeetCode Solution129
1032Binary Search Tree129
1033Advantages of BST over Hash Table129
1034Scramble String LeetCode Solution128
1035Defanging an IP Address LeetCode Solution128
1036Employee Importance LeetCode Solution128
1037Implement Trie (Prefix Tree) Leetcode Solution128
1038Ugly Numbers128
1039Invalid Transactions LeetCode Solution128
1040Build an Array With Stack Operations Leetcode Solution128
1041Minimum Size Subarray Sum128
1042Available Captures for Rook Leetcode Solution128
1043Move all negative elements to end in order with extra space allowed128
1044Construction of Longest Increasing Subsequence (N log N)128
1045String Matching in an Array Leetcode Solution128
1046Boolean Parenthesization Problem128
1047Morris Inorder Traversal128
1048Maximum Product of Indexes of Next Greater on Left and Right128
1049Construct Binary Tree from given Parent Array representation128
1050Number of palindromic paths in a matrix128
1051Balanced Binary Tree128
1052Rearrange an array such that ‘arr[j]’ becomes ‘i’ if ‘arr[i]’ is ‘j’128
1053Longest Bitonic Subsequence127
1054Maximum weight transformation of a given string127
1055Count minimum steps to get the given desired array127
1056Minimum Index Sum of Two Lists127
1057Maximum Sum of 3 Non-Overlapping Subarrays127
1058Maximum difference between frequency of two elements such that element having greater frequency is also greater127
1059Regular Expression Matching Regular Expression Matching LeetCode Solution127
1060Populating Next Right Pointers in Each Node Leetcode Solution127
1061Kth Smallest Element in a Sorted Matrix LeetCode Solution127
1062Add two numbers127
1063Maximum length subsequence with difference between adjacent elements as either 0 or 1127
1064Find Peak Element127
1065Find whether a subarray is in form of a mountain or not127
1066Recover Binary Search Tree Leetcode Solution126
1067Find the minimum distance between two numbers126
1068Validate Binary Search Tree126
1069Divisible Pairs Counting126
1070Lowest Common Ancestor126
1071Custom Sort String Leetcode Solution126
1072Remove Duplicates from Sorted Array II Leetcode Solution126
1073Bitwise AND of Numbers Range LeetCode Solution126
1074Iterative Depth First Traversal of Graph126
1075Find a Peak Element II LeetCode Solution126
1076Day of the Year Leetcode Solution125
1077Path Sum II LeetCode Solution125
1078Combination Sum IV LeetCode Solution125
1079Binary Tree Data Structure125
1080Largest BST Subtree LeetCode Solution125
1081Number of Closed Islands Leetcode Solution125
1082Determine Whether Matrix Can Be Obtained By Rotation LeetCode Solution125
1083Smallest Common Region Leetcode Solution125
1084Maximize Distance to Closest Person LeetCode Solution125
1085Binary Tree Right Side View LeetCode Solution125
1086Search in Sorted Rotated Array125
1087Subarrays with K Different Integers Leetcode Solution124
1088Next Permutation Leetcode Solution124
1089Consecutive Characters LeetCode Solution124
1090Increasing Triplet Subsequence LeetCode Solution124
1091Clone a Binary Tree with Random Pointers124
1092Level of Each node in a Tree from source node124
1093Rearrange array such that even index elements are smaller and odd index elements are greater124
1094Path Sum124
1095Types of Binary Tree124
1096Remove Palindromic Subsequences Leetcode Solution124
1097Number of Students Doing Homework at a Given Time Leetcode Solution124
1098Find Smallest Range Containing Elements from k Lists123
1099Serialize and Deserialize Binary Tree LeetCode Solution123
1100Distinct Subsequences123
1101Print all triplets in sorted array that form AP123
1102Topological Sorting123
1103Kth Smallest Product of Two Sorted Arrays LeetCode Solution123
1104Generate Parentheses Leetcode Solution123
1105Print Next Greater Number of Q queries123
1106Count pairs from two sorted arrays whose sum is equal to a given value x123
1107Number of siblings of a given Node in n-ary Tree123
1108Remove duplicates from sorted array122
1109Cutting a Rod122
1110Constant time range add operation on an array122
1111Find maximum difference between nearest left and right smaller elements122
1112Bottom View of a Binary Tree122
1113Root to Leaf path with target sum Leetcode Solutions122
1114Maximum Product Subarray122
1115Third Maximum Number Leetcode Solution121
1116Find Three Element From Different Three Arrays Such That a + b + c = sum121
1117Convert BST into a Min-Heap without using array121
1118Maximum Binary Tree121
1119Print Right View of a Binary Tree121
1120Count Largest Group Leetcode Solution121
1121Construct Binary Tree from Preorder and Postorder Traversal LeetCode Solution121
1122Write Code to Determine if Two Trees are Identical121
1123Valid Tic-Tac-Toe State LeetCode Solution121
1124Minimum Score Triangulation of Polygon Leetcode Solution121
1125Cells with Odd Values in a Matrix LeetCode Solution120
1126Palindrome Permutation LeetCode Solution120
1127Golomb sequence120
1128Search Insert Position120
1129Mean of Array After Removing Some Elements Leetcode Solution120
1130Longest Subarray of 1’s After Deleting One Element LeetCode Solution120
1131Reformat The String Leetcode Solution120
1132Queries for Number of Distinct Elements in a Subarray120
1133Products of ranges in an array120
1134Iterative method to find ancestors of a given binary tree120
1135Minimum sum of squares of character counts in a given string after removing k characters120
1136Search an Element in Sorted Rotated Array120
1137Construct K Palindrome Strings LeetCode Solution119
1138Minimum Absolute Difference in BST Leetcode Solution119
1139Red-Black Tree Introduction119
1140Prime Palindrome LeetCode Solution119
1141Find a sorted subsequence of size 3 in linear time119
1142Closest Binary Search Tree Value Leetcode Solution119
1143Print modified array after executing the commands of addition and subtraction119
1144Moser-de Bruijn Sequence119
1145Longest Increasing Consecutive Subsequence119
1146Thousand Separator Leetcode Solution119
1147Sum of Even Numbers After Queries119
1148Binary Tree to Binary Search Tree Conversion118
1149Merge two BSTs with limited extra space118
1150Transform a BST to Greater sum Tree118
1151Maximum Product of Splitted Binary Tree LeetCode Solution118
1152Find maximum length Snake sequence118
1153Delete Nodes and Return Forest Leetcode Solution118
1154Bus Routes Leetcode Solution118
1155Decision Tree117
1156Count even length binary sequences with same sum of first and second half bits117
1157K’th Largest element in BST using constant extra space117
1158K maximum sums of overlapping contiguous sub-arrays117
1159Find the smallest binary digit multiple of given number117
1160Swap Nodes In Pairs117
1161Kth Smallest Number in Multiplication Table Leetcode Solution117
1162Check Array Formation Through Concatenation Leetcode Solution117
1163Factorial Trailing Zeroes LeetCode Solution117
1164Number of Orders in the Backlog Leetcode Solution117
1165Possible Bipartition LeetCode Solution117
1166Palindromic Substrings Leetcode Solution117
1167Find Two Non-overlapping Sub-arrays Each With Target Sum LeetCode Solution117
1168Longest Repeated Subsequence117
1169Web Crawler LeetCode Solution116
1170Subset Sum Problem in O(sum) space116
1171Minimum Sideway Jumps LeetCode Solution116
1172Rotate Array116
1173Minimum Cost to Move Chips to The Same Position LeetCode Solution116
1174Compare Strings by Frequency of the Smallest Character Leetcode Solution116
1175Minimum Moves to Equal Array Elements LeetCode Solution116
1176Priority Queue116
1177Maximize sum of consecutive differences in a circular array116
1178Swapping Nodes in a Linked List Leetcode Solution116
1179First Bad Version115
1180Closest Leaf in a Binary Tree LeetCode Solution115
1181Search Suggestions System LeetCode Solution115
1182Find Largest Value in Each Tree Row LeetCode Solution115
1183Diameter of N-Ary Tree LeetCode Solution114
1184Count Pairs Whose Products Exist in Array114
1185Remove Max Number of Edges to Keep Graph Fully Traversable Leetcode Solution114
1186Given a binary tree, how do you remove all the half nodes?114
1187Decrease Elements To Make Array Zigzag LeetCode Solution114
1188Matchsticks to Square Leetcode Solution113
1189Contiguous Array LeetCode Solution113
1190Kth Smallest Element in a BST113
1191Maximum number of segments of lengths a, b and c113
1192Queue Reconstruction by Height113
1193Convert Sorted Array to Binary Search Tree LeetCode Solutions113
1194Moving Stones Until Consecutive Leetcode Solution113
1195Reverse a Path in BST using Queue113
1196Array Queries for multiply replacements and product112
1197Valid Triangle Number112
1198Lowest Common Ancestor in Binary Search Tree112
1199Maximum sum bitonic subarray112
1200Reformat Date LeetCode Solution112
1201Sum of Left Leaves LeetCode Solution112
1202Filter Restaurants by Vegan-Friendly, Price and Distance Leetcode Solution112
1203Write a function to get the intersection point of two Linked Lists112
1204Champagne Tower LeetCode Solution112
1205Maximum Depth Of Binary Tree112
1206Range Sum Query using Sparse Table111
1207Replace two consecutive equal values with one greater111
1208Integer Break LeetCode Solution111
1209Maximum sum of pairs with specific difference111
1210How to print maximum number of A’s using given four keys111
1211New 21 Game111
1212Concatenation of Array LeetCode Solution110
1213Valid Perfect Square LeetCode Solution110
1214Convert Integer to the Sum of Two No-Zero Integers Leetcode Solution110
1215Range Queries for Longest Correct Bracket Subsequence110
1216Guess The Word110
1217Symmetric Tree LeetCode Solution Leetcode Solution110
1218Divide Two Integers Leetcode Solution110
1219Design Skiplist LeetCode Solution110
1220Maximum Value at a Given Index in a Bounded Array LeetCode Solution110
1221Graph and its representation110
1222Path Crossing Leetcode Solution110
1223Check Completeness of a Binary Tree LeetCode Solution109
1224Merge Sort109
1225BST to a Tree with Sum of all Smaller Keys109
1226The kth Factor of n Leetcode Solution109
1227Flatten 2D Vector LeetCode Solution109
1228Check if each internal node of a BST has exactly one child109
1229Perfect Squares LeetCode Solution109
1230Lowest Common Ancestor of a Binary Tree Leetcode Solution109
1231Check for Identical BSTs without building the trees109
1232Maximum sum of a path in a Right Number Triangle109
1233Arithmetic Slices II – Subsequence LeetCode Solution109
1234Print modified array after multiple array range increment operations109
1235Check if all levels of two Binary Tree are anagrams or not108
1236Power of Two108
1237Sliding Window Median Leetcode Solution108
1238Longest Common Prefix Using Word by Word Matching108
1239Parallel Courses II LeetCode Solution108
1240Queries on Probability of Even or Odd Number in given Ranges108
1241Minimum Swaps To Make Sequences Increasing LeetCode Solution108
1242Count Subsets Having Distinct Even Numbers108
1243Image Overlap LeetCode Solution107
1244Count and Toggle Queries on a Binary Array107
1245Mean of range in array107
1246Graph Cloning107
1247Find Minimum in Rotated Sorted Array II LeetCode Solution107
1248Contiguous Array107
1249LRU Cache Leetcode Solution107
1250Largest Plus Sign Leetcode Solution107
1251Maximum Array from Two given Arrays Keeping Order Same107
1252Missing Number107
1253Maximize Elements Using Another Array107
1254Check If a String Can Break Another String Leetcode Solution106
1255Find minimum number of merge operations to make an array palindrome106
1256Bold Words in String LeetCode Solution106
1257Print n terms of Newman-Conway Sequence106
1258Minimum Remove to Make Valid Parentheses LeetCode Solution105
1259Find k-th smallest element in BST (Order Statistics in BST)105
1260Excel Sheet Column Title LeetCode Solution105
1261Verify Preorder Serialization of a Binary Tree105
1262Next greater element104
1263Print Ancestors of a Given Binary Tree Node Without Recursion104
1264Maximum Product Subarray104
1265Merge k Sorted Lists Leetcode Solution104
1266Minimum Time to Collect All Apples in a Tree LeetCode Solution103
1267Smallest Range II Leetcode Solution103
1268Palindrome Partitioning103
1269Check if two nodes are on the same path in a Tree102
1270Min Cost Climbing Stairs LeetCode Solution102
1271Merge Sorted Array101
1272Check in binary array the number represented by a subarray is odd or even101
1273Orderly Queue LeetCode Solution101
1274Peeking Iterator LeetCode Solution100
1275Koko Eating Bananas LeetCode Solution100
1276Check if X can give change to every person in the Queue99
1277Number of elements less than or equal to a given number in a given subarray99
1278Newman–Shanks–Williams prime99
1279Different Ways to Add Parentheses Leetcode Solution99
1280Range Minimum Query (Square Root Decomposition and Sparse Table)97
1281Maximum Sum Increasing Subsequence97
1282Find maximum average subarray of k length97
1283Largest Submatrix With Rearrangements LeetCode Solution97
1284Queries for Decimal Values of Subarrays of a Binary Array96
1285Number of indexes with equal elements in given range96
1286Longest Substring Without Repeating Characters Leetcode Solution96
1287Minimum Total Space Wasted With K Resizing Operations LeetCode Solution95
1288Maximum product of an increasing subsequence95
1289Array Nesting Leetcode Solution95
1290Binary Tree to Binary Search Tree Conversion using STL set94
1291Check given array of size n can represent BST of n levels or not94
1292Arranging Coins Leetcode Solution93
1293Minimum Number of People to Teach LeetCode Solution93
1294Find the Winner of the Circular Game LeetCode Solution92
1295Queries on XOR of greatest odd divisor of the range92
1296Convert to Base -2 LeetCode Solution92
1297Random Pick Index LeetCode Solution92
1298Jump Game IV LeetCode Solution92
1299Encoded String With Shortest Length LeetCode Solution92
1300Reach a Number LeetCode Solution92
1301Convert a BST to a Binary Tree such that sum of all greater keys is added to every key91
1302Minimum Possible Integer After at Most K Adjacent Swaps On Digits LeetCode Solution90
1303Insert Delete GetRandom O(1) Leetcode Solution90
1304Palindrome Number LeetCode Solution88
1305Number of Subsequences That Satisfy the Given Sum Condition LeetCode solution88
1306Add Two Numbers II Leetcode Solution87
1307Vertical Order Traversal of Binary Tree LeetCode Solution87
1308Design Underground System Leetcode Solution86
1309Continuous Subarray Sum LeetCode Solution85
1310Print Maximum Length Chain of Pairs84
1311Detect Capital Leetcode Solution81
1312Design A Leaderboard Leetcode Solution79
1313Top K Frequent Elements LeetCode Solution78
1314Substring with Concatenation of All Words Leetcode Solution78
1315Minimum Swaps to Group All 1’s Together Leetcode Solution77
1316Decode String Leetcode Solution74
1317Minimum Path Sum Leetcode Solution74
1318Binary Tree Inorder Traversal LeetCode Solution72
1319Odd Even Linked List Leetcode Solution72
1320Count Sub Islands LeetCode Solution72
1321Shortest Unsorted Continuous Subarray LeetCode Solution71
1322Shifting Letters LeetCode Solution71
1323Sum Root to Leaf Numbers LeetCode Solution70
1324Maximum Population Year LeetCode Solution70
1325Find the Town Judge LeetCode Solution70
1326Best Meeting Point LeetCode Solution69
1327Find the Town Judge LeetCode Solution68
1328Longest Common Subsequence LeetCode Solution68
1329Design Add and Search Words Data Structure LeetCode Solution67
1330Maximum Population Year LeetCode Solution65
1331Rectangle Overlap LeetCode Solution65
1332Score of Parenthesis LeetCode Solution65
1333Insert into a Sorted Circular Linked List LeetCode Solution62
1334Stone Game IV LeetCode Solution62
1335Flatten Binary Tree to Linked List LeetCode Solution62
1336Range Sum Query 2D – Immutable LeetCode Solution60
1337Valid Triangle Number LeetCode Solution59
1338Is Graph Bipartite? LeetCode Solution58
1339Reveal Cards In Increasing Order Leetcode Solution54
1340Divide Chocolate LeetCode Solution50
1341Step-By-Step Directions From a Binary Tree Node to Another LeetCode Solution42
1342Range Sum of BST LeetCode Solution42
1343Reverse Integer Leetcode Solution40
1344Sort Colors LeetCode Solution37
1345Find K Closest Elements LeetCode Solution34
1346Excel Sheet Column Number LeetCode Solution33
1347Rotate String LeetCode Solution32
1348Maximum Side Length of a Square with Sum Less than or Equal to Threshold LeetCode Solution31
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