Valid Triangle Number LeetCode Solution

Difficulty Level Medium
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Problem Statement

Valid Triangle Number LeetCode Solution – Given an integer array nums, return the number of triplets chosen from the array that can make triangles if we take them as side lengths of a triangle.

Input: nums = [2,2,3,4]
Output: 3
Explanation: Valid combinations are: 
2,3,4 (using the first 2)
2,3,4 (using the second 2)


Once we sort the given  array, we need to find the right limit of the index k for a pair of indices (i, j) chosen to find the count of elements satisfying nums[i] + nums[j] > nums[k] for the triplet (nums[i], nums[j], nums[k]) to form a valid triangle.

We can find this right limit by simply traversing the index ‘s values starting from the index k=j+1 for a pair (i, j) chosen and stopping at the first value of k not satisfying the above inequality. Again, the count of elements nums[k] satisfying nums[i] + nums[j] > nums[k] for the pair of indices (i, j) chosen is given by k – j – 1 as discussed in the last approach.

Further, as discussed in the last approach, when we choose a higher value of index j for a particular i chosen, we need not start from the index j + 1. Instead, we can start off directly from the value of k where we left for the last index j. This helps to save redundant computations.

Valid Triangle Number LeetCode SolutionPin

Code for Valid Triangle Number LeetCode Solution

Java Code:

public class Solution {
    public int triangleNumber(int[] nums) {
        int count = 0;
        for (int i = 0; i < nums.length - 2; i++) {
            int k = i + 2;
            for (int j = i + 1; j < nums.length - 1 && nums[i] != 0; j++) {
                while (k < nums.length && nums[i] + nums[j] > nums[k])
                count += k - j - 1;
        return count;

C++ Code:

class Solution {
    int triangleNumber(vector<int>& nums) {
        sort(nums.begin(), nums.end());
        int n = nums.size(), ans = 0;
        for (int k = 2; k < n; ++k) {
            int i = 0, j = k - 1;
            while (i < j) {
                if (nums[i] + nums[j] > nums[k]) {
                    ans += j - i;
                    j -= 1;
                } else {
                    i += 1;
        return ans;

Complexity Analysis for Valid Triangle Number LeetCode Solution

Time Complexity


Space Complexity


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596Find the smallest positive integer value that cannot be represented as sum of any subset of a given array173
597Minimum number of distinct elements after removing m items172
598Maximum Distance in Array172
599Minimum insertions to form a palindrome with permutations allowed171
600Stone Game LeetCode171
601Same Tree LeetCode Solution171
602Rotate Image LeetCode Solution171
603Sort Characters By Frequency LeetCode Solution171
604Minimum number of subsets with distinct elements171
605How to check if two given sets are disjoint?171
606Word Pattern170
607Remove All Occurrences of a Substring LeetCode Solution170
608Sieve of Eratosthenes170
609Painting Fence Algorithm170
610Permutation in String Leetcode Solution170
611Frog Jump Leetcode Solution170
612XOR Operation in an Array Leetcode Solution170
613Sort Array By Parity LeetCode Solution170
614Find minimum difference between any two elements170
615Find if an Expression has Duplicate Parenthesis or Not170
616K Empty Slots LeetCode170
617Tracking current Maximum Element in a Stack169
618Applications of Breadth First Search and Depth First Search169
619Printing brackets in Matrix Chain Multiplication Problem169
620Isomorphic Strings169
621Smallest Good Base169
622Best Time to Buy and Sell Stock LeetCode Solution169
623Word Wrap Problem169
624House Robber169
625Defanging an IP Address Leetcode Solution169
626Replace Elements with Greatest Element on Right Side Leetcode Solution169
627Bubble sort using two Stacks169
628Distance of nearest cell having 1 in a binary matrix169
629Minimum Depth of Binary Tree Leetcode Solution169
630Reverse a stack without using extra space in O(n)169
631Maximum Consecutive Numbers Present in an Array168
632Longest Substring with At Most K Distinct Characters LeetCode Solution168
633Segregate 0s and 1s in an Array168
634Minimum Cost to Hire K Workers168
635Longest Increasing Subsequence168
636License Key Formatting Leetcode Solution168
637Find the Duplicate Number LeetCode Solution168
638Find Sum of all unique sub-array sum for a given array168
639Optimal Account Balancing LeetCode Solution167
640Moving Average from Data Stream Leetcode Solution167
641Valid Palindrome II Leetcode Solution167
642Non-overlapping sum of two sets167
643Binary Tree Zigzag Level Order Traversal LeetCode Solution167
644Iterative Method to find Height of Binary Tree167
645Find Maximum Level sum in Binary Tree167
646Coin Change Problem167
647Wiggle Sort167
648Maximum difference between first and last indexes of an element in array167
649Count Good Nodes in Binary Tree Leetcode Solution167
650Maximum Number of Occurrences of a Substring Leetcode Solution166
651Kth Missing Positive Number Leetcode Solution166
652Merge Two Balanced Binary Search Trees166
653Sum of All Odd Length Subarrays Leetcode Solution166
654How to Create Mergable Stack?166
655Check If It Is a Straight Line Leetcode Solution166
656GCD Of Two Numbers166
657Employee Free Time LeetCode Solution166
658Queries for counts of array elements with values in given range166
659Best Time to Buy and Sell Stock with Cooldown Leetcode Solution166
660Minimum Number of Steps to Make Two Strings Anagram Leetcode Solutions166
661Convert an array to reduced form165
662Longest Substring with At Least K Repeating Characters LeetCode Solution165
663Letter Combinations of a Phone Number165
664Path With Maximum Minimum Value LeetCode Solution165
665Strobogrammatic Number LeetCode Solution165
666Find the Distance Value Between Two Arrays Leetcode Solution165
667Valid Palindrome165
668Find Largest d in Array such that a + b + c = d165
669Flipping an Image LeetCode Solution165
670Find pairs with given sum such that elements of pair are in different rows164
671Delete consecutive same words in a sequence164
672Reorganize String164
673Maximum Number of Coins You Can Get Leetcode Solution164
674Partition Labels LeetCode Solution164
675Number of Provinces Leetcode Solution164
676Permutation Sequence LeetCode Solution163
677Longest Increasing Path in a Matrix LeetCode Solution163
678Inorder Successor of a node in Binary Tree163
679Power of Four Leetcode Solution163
680Print the Fibonacci numbers in reverse order163
681Check If Two String Arrays are Equivalent Leetcode Solution163
682Valid Perfect Square Leetcode Solution163
683Number of Dice Rolls With Target Sum LeetCode Solution163
684Edit Distance LeetCode Solution163
685Rearrange an array in order – smallest, largest, 2nd smallest, 2nd largest163
686Reducing Dishes LeetCode Solution163
687Recover Binary Search Tree163
688Populating Next Right Pointers in Each Node163
689Dynamic Programming Basics162
690Remove Invalid Parentheses Leetcode Solution162
691Form minimum number from given sequence162
692Check if a queue can be sorted into another queue using a stack162
693Partition Array Into Three Parts With Equal Sum Leetcode Solution162
694Lucky Numbers in a Matrix Leetcode Solution162
695Sort Array by Increasing Frequency Leetcode Solution162
696Increasing Decreasing String Leetcode Solution162
697Construct BST from given Preorder Traversal162
698BFS vs DFS for Binary Tree162
699K Empty Slots162
700Reversing a Queue using Recursion161
701Maximum Product of Two Elements in an Array Leetcode Solution161
702Find whether an array is subset of another array161
703Convert a Number to Hexadecimal Leetcode Solution161
704To Lower Case Leetcode Solution161
705Merge Two Binary Trees LeetCode Solution161
706Binary Tree zigzag level order Traversal161
707Factorial Trailing Zeroes Leetcode Solution161
708String to Integer (atoi) LeetCode Solution161
709Subset Sum Leetcode161
710Ugly Number Leetcode Solution161
711Robot Room Cleaner Leetcode Solution161
712Reservoir Sampling161
713Restore IP Addresses Leetcode Solution160
714Keyboard Row Leetcode Solution160
715Delete Nth node from the end of the given linked list160
716Binomial Coefficient160
717Find Leaves of Binary Tree LeetCode Solution160
718Reverse Only Letters LeetCode Solution160
719Majority Element II Leetcode Solution160
720Find the Smallest Divisor given a Threshold Leetcode Solution160
721Bulb Switcher LeetCode Solution159
722Add and Search Word – Data structure design LeetCode159
723Unique Paths II Leetcode Solution159
724Perform String Shifts Leetcode159
725Numbers with prime frequencies greater than or equal to k159
726Decompress Run-Length Encoded List Leetcode Solution159
727Find the largest multiple of 3159
728Find Pair with Greatest Product in Array158
729Find the node with minimum value in a Binary Search Tree158
730Minimum Cost For Tickets Leetcode Solution158
731Finding K closest element158
732Maximum Product of Three Numbers LeetCode Solution158
733Morris Traversal158
734Hamming Distance Leetcode Solution158
735Maximum 69 Number Leetcode Solution158
736Sorted Linked List to Balanced BST157
737Student Attendance Record I Leetcode Solution157
738Minimum Distance Between BST Nodes Leetcode Solution157
739Find Maximum Depth of Nested Parenthesis in a String157
740Maximum Depth of N-ary Tree Leetcode Solution157
741Merge K Sorted Linked Lists157
742String Compression LeetCode Solution157
743Word Pattern LeetCode Solution157
744Sum of f(a[i], a[j]) over all pairs in an array of n integers157
745Invert Binary Tree LeetCode Solution157
746Number of Islands II LeetCode Solution157
747First Unique Character in a String LeetCode Solution157
748Kth ancestor of a node in binary tree156
749Longest Span with same Sum in two Binary arrays156
750Non-decreasing Array LeetCode Solution156
751Generate all possible sorted arrays from alternate elements of two given sorted arrays156
752Check If Array Pairs Are Divisible by k LeetCode Solution156
753Queue based approach for first non-repeating character in a stream156
754Special Array With X Elements Greater Than or Equal X Leetcode Solution156
755Diagonal Traversal of Binary Tree156
756Tiling Problem156
757Best Meeting Point LeetCode Solution156
758Binary Tree Maximum Path Sum LeetCode Solution156
759Symmetric Tree Leetcode Solution156
760Find All Duplicates in an Array LeetCode Solution156
761Find unique character in a string156
762Minimum Height Trees156
763Largest subarray with equal number of 0s and 1s156
764Rank Transform of an Array Leetcode Solution156
765Maximum Length of a Concatenated String with Unique Characters Leetcode Solution155
766Largest Rectangle in Histogram LeetCode Solution155
767Stack Permutations (Check if an array is stack permutation of other)155
768Evaluate Reverse Polish Notation LeetCode Solution155
769Largest rectangular sub-matrix whose sum is 0155
770Minimum time required to rot all oranges155
771Minimize Maximum Pair Sum in Array LeetCode Solution155
772Search a 2D Matrix II Leetcode Solution155
773Final Prices With a Special Discount in a Shop Leetcode Solution155
774Elements to be added so that all elements of a range are present in array155
775Find if Path Exists in Graph Leetcode Solution155
776Find Median from Data Stream LeetCode Solution155
777Jump Game155
778Valid Number154
779Split a String in Balanced Strings Leetcode Solution154
780k-th missing element in increasing sequence which is not present in a given sequence154
781Remove Nth Node From End of List Leetcode Solution154
782Count items common to both the lists but with different prices154
783Remove brackets from an algebraic string containing + and – operators154
784Maximum Difference Between Increasing Elements LeetCode Solution154
785Snakes and Ladders LeetCode Solution154
786Linked List Cycle154
787Program for Bridge and Torch problem154
788Transpose Graph154
789Partition to K Equal Sum Subsets Leetcode Solution154
790Race Car LeetCode Solution154
791Count quadruples from four sorted arrays whose sum is equal to a given value x153
792Sort an array according to the order defined by another array153
793Get Maximum in Generated Array Leetcode Solution153
794N-Queens LeetCode Solution153
795Last Stone Weight II LeetCode Solution153
796Nearest Exit from Entrance in Maze LeetCode Solution153
797Search in a Binary Search Tree Leetcode Solution153
798Deletion in a Binary Tree153
799Minimum Jumps to Reach Home LeetCode Solution153
800Number of NGEs to the Right153
801Total Numbers With no Repeated Digits in a Range152
802Merge Sorted Array LeetCode Solution152
803String comparison containing wildcards152
804Growable array based stack152
805Minimum swaps to make sequences increasing152
806Interval Tree152
807Crawler Log Folder Leetcode Solution152
808Minimum number of jumps to reach end152
809Check if Two Expressions With Brackets are Same152
810Iterative Preorder Traversal152
811A Space Optimized DP solution for 0-1 Knapsack Problem152
812Minimum Time Visiting All Points Leetcode Solution152
813Priority Queue using doubly linked list152
814Subarray Product Less Than K LeetCode Solution152
815Check for Palindrome after every character replacement Query152
816Maximum Profit in Job Scheduling Leetcode Solution152
817Remove Duplicates from Sorted List LeetCode Solution152
818Remove Duplicates from Sorted List II152
819Number Complement Leetcode Solution152
820Print a Binary Tree in Vertical Order152
821Course Schedule II – LeetCode152
822Relative Ranks Leetcode Solution152
823Reorder Data in Log Files LeetCode Solution152
824Form Minimum Number From Given Sequence151
825Find all triplets with zero sum151
826Sort Array By Parity II Leetcode Solution151
827Spiral Matrix II Leetcode Solution151
828Maximum size subarray sum equals k151
829Nested List Weight Sum II LeetCode Solution151
830One Edit Distance LeetCode Solution151
831Base 7 Leetcode Solution151
832Path with maximum average value150
833Longest Subarray Having Count of 1s One More than Count of 0s150
834Convert BST to Min Heap150
835Circular Queue150
836Valid Parentheses Leetcode Solution150
837Brick Wall LeetCode Solution150
838Given an Array of Pairs Find all Symmetric Pairs in it150
839Regular Expression Matching150
840Maximum Nesting Depth of the Parentheses Leetcode Solution150
841Alien Dictionary LeetCode Solution150
842Subsequence of Size K With the Largest Even Sum LeetCode Solution149
843Friends Pairing Problem149
844Subset with sum divisible by m149
845Sort Colors149
846Partition List Leetcode Solution149
847Make Two Arrays Equal by Reversing Sub-arrays Leetcode Solution149
848Top K Frequent Words LeetCode Solution149
849Check if a given array can represent Preorder Traversal of Binary Search Tree149
850Find the subarray with least average149
851Clone Graph LeetCode Solution149
852Minimum Number of Taps to Open to Water a Garden LeetCode Solution149
853Find All Possible Recipes from Given Supplies LeetCode Solution149
854Check whether a given Binary Tree is Complete or not149
855Can Place Flowers LeetCode Solution149
856Insert into a Binary Search Tree Leetcode Solution149
857Level order Traversal in Spiral Form148
858Tree Traversal (Preorder, Inorder & Postorder)148
859Guess Number Higher or Lower LeetCode Solution148
860Find Maximum Sum Possible Equal Sum of Three Stacks148
861Design a Stack With Increment Operation Leetcode Solution148
862Find the Only Repetitive Element Between 1 to N-1148
863Permutation Coefficient148
864Matrix Chain Multiplication148
865Count Negative Numbers in a Sorted Matrix LeetCode Solution148
866Sequences of given length where every element is more than or equal to twice of previous148
867Binary Search Tree Search and Insertion148
868Count Distinct Elements in Every Window of Size K148
869Identify and Mark Unmatched Parenthesis in an Expression147
870Balanced Expression with Replacement147
871Design Browser History LeetCode Solution147
872Missing Element in Sorted Array LeetCode Solution147
873Minimum Sum Path in a Triangle147
874Number of Days Between Two Dates LeetCode Solution147
875Range LCM Queries147
876Diagonal Traverse LeetCode Solution147
877Repeated Substring Pattern LeetCode Solution147
878Distinct adjacent elements in an array147
879Diagonal Traversal LeetCode Solution147
880Water Bottles Leetcode Solution147
881Sum of nearest smaller and greater number147
882Union and Intersection of two Linked Lists146
883Best Time to Buy and Sell Stock with Transaction Fee Leetcode Solution146
884Check if an Array is Stack Sortable146
885Insert Delete GetRandom146
886Check if stack elements are pairwise consecutive146
887Time Based Key-Value Store LeetCode Solution146
888Sorted Array to Balanced BST146
889Maximum Score After Splitting a String Leetcode Solution146
890BFS for Disconnected Graph146
891An Interesting Method to generate Binary Numbers from 1 to n146
892Convert Sorted List to Binary Search Tree146
893Three way partitioning of an array around a given range146
894Brightest Position on Street LeetCode Solution146
895GCDs of given index ranges in an array146
896Daily Temperatures Leetcode Solution146
897K’th Largest Element in BST when modification to BST is not allowed146
898Shortest Word Distance Leetcode Solution146
899Guess Number Higher or Lower II146
900LCS (Longest Common Subsequence) of three strings146
901Minimum sum of multiplications of n numbers146
902Rearrange an Array Such that arr[i] is equal to i146
903Minimum Swaps to Make Strings Equal Leetcode Solution145
904Destination City Leetcode Solution145
905Least Number of Unique Integers after K Removals Leetcode Solution145
906Lemonade Change Leetcode Solution145
907Delete And Earn145
908Check if the given array can represent Level Order Traversal of Binary Search Tree145
909Count ways to reach the nth stair using step 1, 2 or 3145
910Range sum queries without updates145
911Robot Bounded In Circle LeetCode Solution145
912Rearrange Array such that arr[i] >= arr[j] if i is even and arr[i] <= arr[j] if i is odd and j < i145
913Find distance between two nodes of a Binary Tree145
914Rearrange Spaces Between Words Leetcode Solution144
915Print Fibonacci sequence using 2 variables144
916Merge Two Sorted Lists Leetcode144
917Spiral Matrix III LeetCode Solution144
919Palindrome Partitioning Leetcode Solution144
920Find Common Characters Leetcode Solution144
921Vertical sum in a given binary tree144
922Number of Distinct Islands Leetcode Solution144
923Special Positions in a Binary Matrix Leetcode Solution143
924Construct the Rectangle Leetcode Solution143
925Maximum Subarray Sum Excluding Certain Elements143
926A program to check if a binary tree is BST or not143
927Maximum Frequency Stack Leetcode Solution143
928Construct BST from its given Level Order Traversal143
929Alien Dictionary143
930Minimum Height Trees LeetCode Solution143
931Stone Game II Leetcode143
932Split Array Into Consecutive Subsequences143
933Averages of Levels in Binary Tree143
9343 Sum143
935Construct Complete Binary Tree from its Linked List Representation143
936Set Matrix Zeroes Leetcode Solution142
937Iterative Postorder Traversal Using Two Stacks142
938Difference Array | Range update query in O(1)142
939Strongly Connected Component142
940Binary Tree Longest Consecutive Sequence LeetCode Solution142
941Lexicographical Numbers Leetcode Solution142
942Queries for GCD of all numbers of an array except elements in a given range142
943Check if any two intervals overlap among a given set of intervals142
944Infix to Postfix142
945Remove Duplicates from Sorted List II LeetCode Solution142
946Queue using Stacks142
947Longest Palindromic Subsequence142
948Largest area rectangular sub-matrix with equal number of 1’s and 0’s142
949Trim a Binary Search Tree142
950Find all permuted rows of a given row in a matrix141
951All Unique Triplets that Sum up to a Given Value141
952Unique Paths II141
953Sliding Window Maximum141
954Collect maximum points in a grid using two traversals141
955Analyze User Website Visit Pattern LeetCode Solution141
956Count Submatrices With All Ones LeetCode Solution141
957Count Subarrays with Same Even and Odd Elements141
958Shuffle 2n integers as without using extra space141
959Binary array after M range toggle operations141
960Count subarrays where second highest lie before highest140
961Merging Intervals140
962Word Break140
963Minesweeper LeetCode Solution140
964Dividing Array into Pairs With Sum Divisible by K140
965Sign of the Product of an Array LeetCode Solution140
966Pattern Occurrences using Stack140
967Reverse Nodes in K-Group140
968Create Maximum Number140
969Can Make Arithmetic Progression From Sequence Leetcode Solution140
970Intersection of Two Linked Lists LeetCode Solution140
971Three Consecutive Odds Leetcode Solution140
972Find postorder traversal of BST from preorder traversal140
973Number of Equivalent Domino Pairs Leetcode Solution140
974Palindrome Partitioning139
975Maximum Product Subarray139
976Count pair with Given Sum139
977Symmetric Tree139
978Kth Smallest Element in a BST Leetcode Solution139
979Count Primes in Ranges139
980Longest Nice Substring LeetCode Solution139
981Length of Longest Fibonacci Subsequence139
982The Painter’s Partition Problem139
983Level Order Traversal of Binary Tree139
984Median of Two Sorted Arrays139
985Find the Difference Leetcode Solution139
986Product of Array Except Self LeetCode Solution139
987Binary Search Tree Delete Operation139
988Height of a generic tree from parent array139
989Newman-Conway Sequence139
990Find Maximum of Minimum for Every Window Size in a Given Array138
991Check If a Word Occurs As a Prefix of Any Word in a Sentence Leetcode Solution138
992My Calendar I LeetCode Solution138
993Asteroid Collision LeetCode Solution138
994Maximize Sum of Array after K Negations Leetcode Solution138
995K Closest Points to Origin Leetcode Solution138
996Segment Tree138
997Maximum Product of Indexes of Next Greater on Left and Right137
998Boundary Traversal of binary tree137
999Number Of Longest Increasing Subsequence137
1000Depth First Search (DFS) for a Graph137
1001Find Duplicate Subtrees137
1002Compute nCr % p137
1003Climbing stairs137
1004Valid Boomerang Leetcode Solution137
1005Maximum Length of Repeated Subarray137
1006Merge Sort137
1007Find the First Circular Tour that visits all the Petrol Pumps137
1008Largest Number Leetcode Solution137
1009Shortest Completing Word Leetcode Solution137
1010Largest divisible pairs subset137
1011Friends Of Appropriate Ages LeetCode Solution137
1012Maximum subsequence sum such that no three are consecutive137
1013The Maze III LeetCode Solution137
1014Double the first element and move zero to end137
1015Boolean Parenthesization Problem136
1016Construction of Longest Increasing Subsequence (N log N)136
1017First missing positive136
1018Kill Process LeetCode Solution136
1019Largest Substring Between Two Equal Characters Leetcode Solution136
1020Morris Inorder Traversal136
1021Partition Equal Subset Sum136
1022Maximum weight transformation of a given string136
1023Insertion in a Binary Tree136
1024Construct Binary Tree from given Parent Array representation136
1025String Matching in an Array Leetcode Solution136
1026Serialize and Deserialize Binary Tree136
1027Breadth First Search (BFS) for a Graph136
1028Level order traversal using two Queues136
1029Maximum Number of Ways to Partition an Array LeetCode Solution136
1030Make The String Great Leetcode Solution136
1031Advantages of BST over Hash Table135
1032Number of palindromic paths in a matrix135
1033Minimum Index Sum of Two Lists135
1034Find number of pairs in an array such that their XOR is 0135
1035Decrypt String from Alphabet to Integer Mapping Leetcode Solution135
1036Binary Search Tree135
1037Graph Valid Tree LeetCode Solution135
1038K maximum sums of overlapping contiguous sub-arrays135
1039Next Greater Element III LeetCode Solution135
1040Rearrange an array such that ‘arr[j]’ becomes ‘i’ if ‘arr[i]’ is ‘j’135
1041Longest subsequence such that difference between adjacents is one135
1042Build an Array With Stack Operations Leetcode Solution135
1043Scramble String LeetCode Solution135
1044Rearrange array such that even positioned are greater than odd134
1045Design Hit Counter LeetCode Solution134
1046Custom Sort String Leetcode Solution134
1047Available Captures for Rook Leetcode Solution134
1048Ugly Numbers134
1049Maximum Sum of 3 Non-Overlapping Subarrays134
1050Validate Binary Search Tree134
1051Defanging an IP Address LeetCode Solution133
1052Iterative Depth First Traversal of Graph133
1053Maximum difference between frequency of two elements such that element having greater frequency is also greater133
1054Employee Importance LeetCode Solution133
1055Bitwise AND of Numbers Range LeetCode Solution133
1056Implement Trie (Prefix Tree) Leetcode Solution133
1057Add two numbers133
1058Invalid Transactions LeetCode Solution133
1059Ugly Number II LeetCode Solution133
1060Balanced Binary Tree133
1061Generate Parentheses Leetcode Solution132
1062Path Sum II LeetCode Solution132
1063Count pairs from two sorted arrays whose sum is equal to a given value x132
1064Search in Sorted Rotated Array132
1065Maximum length subsequence with difference between adjacent elements as either 0 or 1132
1066Move all negative elements to end in order with extra space allowed132
1067Find Peak Element132
1068Super Ugly Number132
1069Recover Binary Search Tree Leetcode Solution132
1070Count minimum steps to get the given desired array132
1071Lowest Common Ancestor132
1072Determine Whether Matrix Can Be Obtained By Rotation LeetCode Solution131
1073Kth Smallest Element in a Sorted Matrix LeetCode Solution131
1074Subarrays with K Different Integers Leetcode Solution131
1075Remove Duplicates from Sorted Array II Leetcode Solution131
1076Populating Next Right Pointers in Each Node Leetcode Solution131
1077Regular Expression Matching Regular Expression Matching LeetCode Solution131
1078Find a Peak Element II LeetCode Solution131
1079Binary Tree Right Side View LeetCode Solution131
1080Number of Students Doing Homework at a Given Time Leetcode Solution131
1081Largest BST Subtree LeetCode Solution131
1082Longest Bitonic Subsequence131
1083Combination Sum IV LeetCode Solution130
1084Number of siblings of a given Node in n-ary Tree130
1085Root to Leaf path with target sum Leetcode Solutions130
1086Smallest Common Region Leetcode Solution130
1087Day of the Year Leetcode Solution130
1088Minimum Size Subarray Sum130
1089Clone a Binary Tree with Random Pointers130
1090Find whether a subarray is in form of a mountain or not130
1091Number of Closed Islands Leetcode Solution130
1092Rearrange array such that even index elements are smaller and odd index elements are greater130
1093Remove Palindromic Subsequences Leetcode Solution129
1094Serialize and Deserialize Binary Tree LeetCode Solution129
1095Find the minimum distance between two numbers129
1096Distinct Subsequences129
1097Maximize Distance to Closest Person LeetCode Solution129
1098Convert BST into a Min-Heap without using array129
1099Level of Each node in a Tree from source node129
1100Kth Smallest Product of Two Sorted Arrays LeetCode Solution129
1101Find maximum difference between nearest left and right smaller elements129
1102Find Smallest Range Containing Elements from k Lists129
1103Types of Binary Tree129
1104Next Permutation Leetcode Solution129
1105Binary Tree Data Structure129
1106Count Largest Group Leetcode Solution129
1107Consecutive Characters LeetCode Solution129
1108Increasing Triplet Subsequence LeetCode Solution129
1109Print all triplets in sorted array that form AP128
1110Divisible Pairs Counting128
1111Find Three Element From Different Three Arrays Such That a + b + c = sum128
1112Remove duplicates from sorted array128
1113Construct Binary Tree from Preorder and Postorder Traversal LeetCode Solution128
1114Cutting a Rod128
1115Iterative method to find ancestors of a given binary tree128
1116Third Maximum Number Leetcode Solution128
1117Path Sum128
1118Constant time range add operation on an array128
1119Valid Tic-Tac-Toe State LeetCode Solution128
1120Maximum Product Subarray127
1121Reformat The String Leetcode Solution127
1122Longest Subarray of 1’s After Deleting One Element LeetCode Solution127
1123Products of ranges in an array127
1124Palindrome Permutation LeetCode Solution127
1125Minimum Absolute Difference in BST Leetcode Solution127
1126Prime Palindrome LeetCode Solution127
1127Sum of Even Numbers After Queries127
1128Cells with Odd Values in a Matrix LeetCode Solution126
1129Bottom View of a Binary Tree126
1130Mean of Array After Removing Some Elements Leetcode Solution126
1131Print Right View of a Binary Tree126
1132Minimum Score Triangulation of Polygon Leetcode Solution126
1133Print Next Greater Number of Q queries126
1134Search Insert Position126
1135Search an Element in Sorted Rotated Array125
1136Topological Sorting125
1137Delete Nodes and Return Forest Leetcode Solution125
1138Thousand Separator Leetcode Solution125
1139Write Code to Determine if Two Trees are Identical125
1140Moser-de Bruijn Sequence125
1141Merge two BSTs with limited extra space125
1142Swap Nodes In Pairs124
1143Construct K Palindrome Strings LeetCode Solution124
1144Minimum sum of squares of character counts in a given string after removing k characters124
1145Closest Binary Search Tree Value Leetcode Solution124
1146Subset Sum Problem in O(sum) space124
1147Maximum Binary Tree124
1148Palindromic Substrings Leetcode Solution124
1149Red-Black Tree Introduction124
1150Longest Increasing Consecutive Subsequence124
1151Priority Queue124
1152Print modified array after executing the commands of addition and subtraction123
1153Golomb sequence123
1154Possible Bipartition LeetCode Solution123
1155Find maximum length Snake sequence123
1156Check Array Formation Through Concatenation Leetcode Solution123
1157Find Two Non-overlapping Sub-arrays Each With Target Sum LeetCode Solution123
1158Diameter of N-Ary Tree LeetCode Solution123
1159Bus Routes Leetcode Solution123
1160Find a sorted subsequence of size 3 in linear time122
1161Maximum Product of Splitted Binary Tree LeetCode Solution122
1162Remove Max Number of Edges to Keep Graph Fully Traversable Leetcode Solution122
1163Transform a BST to Greater sum Tree122
1164Search Suggestions System LeetCode Solution122
1165Find Largest Value in Each Tree Row LeetCode Solution122
1166Kth Smallest Number in Multiplication Table Leetcode Solution122
1167Rotate Array122
1168Queries for Number of Distinct Elements in a Subarray122
1169Minimum Sideway Jumps LeetCode Solution122
1170Maximize sum of consecutive differences in a circular array122
1171Longest Repeated Subsequence121
1172Find the smallest binary digit multiple of given number121
1173Compare Strings by Frequency of the Smallest Character Leetcode Solution121
1174Decision Tree121
1175Binary Tree to Binary Search Tree Conversion121
1176Count even length binary sequences with same sum of first and second half bits121
1177Minimum Cost to Move Chips to The Same Position LeetCode Solution120
1178Web Crawler LeetCode Solution120
1179Lowest Common Ancestor in Binary Search Tree120
1180First Bad Version120
1181Convert Sorted Array to Binary Search Tree LeetCode Solutions120
1182Matchsticks to Square Leetcode Solution120
1183Factorial Trailing Zeroes LeetCode Solution120
1184Swapping Nodes in a Linked List Leetcode Solution120
1185Valid Triangle Number119
1186Contiguous Array LeetCode Solution119
1187Decrease Elements To Make Array Zigzag LeetCode Solution119
1188Maximum sum bitonic subarray119
1189Queue Reconstruction by Height119
1190K’th Largest element in BST using constant extra space119
1191Reverse a Path in BST using Queue119
1192Number of Orders in the Backlog Leetcode Solution119
1193Range Queries for Longest Correct Bracket Subsequence118
1194Count Pairs Whose Products Exist in Array118
1195Maximum sum of pairs with specific difference118
1196Closest Leaf in a Binary Tree LeetCode Solution118
1197Reformat Date LeetCode Solution118
1198Sum of Left Leaves LeetCode Solution118
1199Given a binary tree, how do you remove all the half nodes?118
1200Moving Stones Until Consecutive Leetcode Solution118
1201Minimum Moves to Equal Array Elements LeetCode Solution118
1202Maximum number of segments of lengths a, b and c118
1203How to print maximum number of A’s using given four keys118
1204Graph and its representation118
1205Lowest Common Ancestor of a Binary Tree Leetcode Solution118
1206Array Queries for multiply replacements and product117
1207Kth Smallest Element in a BST117
1208Guess The Word117
1209Path Crossing Leetcode Solution116
1210Replace two consecutive equal values with one greater116
1211Convert Integer to the Sum of Two No-Zero Integers Leetcode Solution116
1212Champagne Tower LeetCode Solution116
1213Filter Restaurants by Vegan-Friendly, Price and Distance Leetcode Solution116
1214Minimum Swaps To Make Sequences Increasing LeetCode Solution115
1215Perfect Squares LeetCode Solution115
1216Arithmetic Slices II – Subsequence LeetCode Solution115
1217Integer Break LeetCode Solution115
1218Concatenation of Array LeetCode Solution115
1219Range Sum Query using Sparse Table115
1220Check if each internal node of a BST has exactly one child114
1221Check Completeness of a Binary Tree LeetCode Solution114
1222Power of Two114
1223Maximum Depth Of Binary Tree114
1224Write a function to get the intersection point of two Linked Lists114
1225Flatten 2D Vector LeetCode Solution114
1226Divide Two Integers Leetcode Solution114
1227Mean of range in array114
1228Maximum sum of a path in a Right Number Triangle114
1229Design Skiplist LeetCode Solution114
1230BST to a Tree with Sum of all Smaller Keys114
1231LRU Cache Leetcode Solution114
1232The kth Factor of n Leetcode Solution114
1233Maximize Elements Using Another Array113
1234Bold Words in String LeetCode Solution113
1235Longest Common Prefix Using Word by Word Matching113
1236Queries on Probability of Even or Odd Number in given Ranges113
1237Find Minimum in Rotated Sorted Array II LeetCode Solution113
1238Valid Perfect Square LeetCode Solution113
1239Print modified array after multiple array range increment operations113
1240New 21 Game113
1241Contiguous Array113
1242Check if all levels of two Binary Tree are anagrams or not113
1243Check for Identical BSTs without building the trees113
1244Largest Plus Sign Leetcode Solution113
1245Print Ancestors of a Given Binary Tree Node Without Recursion112
1246Maximum Value at a Given Index in a Bounded Array LeetCode Solution112
1247Sliding Window Median Leetcode Solution112
1248Parallel Courses II LeetCode Solution112
1249Print n terms of Newman-Conway Sequence112
1250Maximum Array from Two given Arrays Keeping Order Same111
1251Symmetric Tree LeetCode Solution Leetcode Solution111
1252Find k-th smallest element in BST (Order Statistics in BST)111
1253Merge k Sorted Lists Leetcode Solution111
1254Maximum Product Subarray111
1255Count Subsets Having Distinct Even Numbers111
1256Graph Cloning111
1257Find minimum number of merge operations to make an array palindrome111
1258Missing Number110
1259Smallest Range II Leetcode Solution110
1260Minimum Remove to Make Valid Parentheses LeetCode Solution110
1261Count and Toggle Queries on a Binary Array110
1262Check if two nodes are on the same path in a Tree110
1263Number of elements less than or equal to a given number in a given subarray109
1264Verify Preorder Serialization of a Binary Tree109
1265Next greater element109
1266Image Overlap LeetCode Solution108
1267Excel Sheet Column Title LeetCode Solution108
1268Check If a String Can Break Another String Leetcode Solution108
1269Koko Eating Bananas LeetCode Solution107
1270Different Ways to Add Parentheses Leetcode Solution107
1271Orderly Queue LeetCode Solution107
1272Palindrome Partitioning107
1273Min Cost Climbing Stairs LeetCode Solution107
1274Minimum Time to Collect All Apples in a Tree LeetCode Solution106
1275Peeking Iterator LeetCode Solution105
1276Largest Submatrix With Rearrangements LeetCode Solution105
1277Newman–Shanks–Williams prime105
1278Check if X can give change to every person in the Queue105
1279Longest Substring Without Repeating Characters Leetcode Solution104
1280Check in binary array the number represented by a subarray is odd or even104
1281Merge Sorted Array103
1282Array Nesting Leetcode Solution102
1283Range Minimum Query (Square Root Decomposition and Sparse Table)102
1284Arranging Coins Leetcode Solution101
1285Maximum Sum Increasing Subsequence101
1286Encoded String With Shortest Length LeetCode Solution100
1287Find maximum average subarray of k length100
1288Maximum product of an increasing subsequence99
1289Queries for Decimal Values of Subarrays of a Binary Array99
1290Number of indexes with equal elements in given range99
1291Minimum Total Space Wasted With K Resizing Operations LeetCode Solution99
1292Minimum Number of People to Teach LeetCode Solution98
1293Convert to Base -2 LeetCode Solution98
1294Convert a BST to a Binary Tree such that sum of all greater keys is added to every key97
1295Random Pick Index LeetCode Solution97
1296Reach a Number LeetCode Solution96
1297Add Two Numbers II Leetcode Solution96
1298Vertical Order Traversal of Binary Tree LeetCode Solution96
1299Find the Winner of the Circular Game LeetCode Solution96
1300Continuous Subarray Sum LeetCode Solution96
1301Binary Tree to Binary Search Tree Conversion using STL set96
1302Jump Game IV LeetCode Solution95
1303Check given array of size n can represent BST of n levels or not95
1304Palindrome Number LeetCode Solution95
1305Queries on XOR of greatest odd divisor of the range95
1306Number of Subsequences That Satisfy the Given Sum Condition LeetCode solution94
1307Minimum Possible Integer After at Most K Adjacent Swaps On Digits LeetCode Solution94
1308Insert Delete GetRandom O(1) Leetcode Solution94
1309Design Underground System Leetcode Solution90
1310Print Maximum Length Chain of Pairs89
1311Detect Capital Leetcode Solution87
1312Design A Leaderboard Leetcode Solution86
1313Minimum Swaps to Group All 1’s Together Leetcode Solution83
1314Top K Frequent Elements LeetCode Solution83
1315Substring with Concatenation of All Words Leetcode Solution83
1316Binary Tree Inorder Traversal LeetCode Solution81
1317Count Sub Islands LeetCode Solution80
1318Minimum Path Sum 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 Solution74
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
1332Flatten Binary Tree to Linked List LeetCode Solution67
1333Stone Game IV LeetCode Solution67
1334Insert into a Sorted Circular Linked List LeetCode Solution66
1335Score of Parenthesis LeetCode Solution66
1336Range Sum Query 2D – Immutable LeetCode Solution66
1337Reveal Cards In Increasing Order Leetcode Solution63
1338Valid Triangle Number LeetCode Solution62
1339Is Graph Bipartite? LeetCode Solution62
1340Divide Chocolate LeetCode Solution53
1341Step-By-Step Directions From a Binary Tree Node to Another LeetCode Solution48
1342Reverse Integer Leetcode Solution45
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
1347Rotate String LeetCode Solution37
1348Excel Sheet Column Number LeetCode Solution37
1349Maximum Size Subarray Sum Equals k Leetcode Solution20
1350H-Index Leetcode Solution19
1351High Five LeetCode Solution18
1352Insert Delete GetRandom O(1) – Duplicates allowed LeetCode Solution9
1353Unique Binary Search Trees LeetCode Solution9
1354Monotonic Array Leetcode Solution7
1355Swim in Rising Water LeetCode Solution2
1356Valid Triangle Number LeetCode Solution1
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