Lowest Common Ancestor of a Binary Search Tree Leetcode Solution

Difficulty Level Easy
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Problem Statement:

Lowest Common Ancestor of a Binary Search Tree Leetcode Solution – Given a binary search tree (BST), find the lowest common ancestor (LCA) node of two given nodes in the BST.

Note: “The lowest common ancestor is defined between two nodes p and q as the lowest node in T that has both p and q as descendants (where we allow a node to be a descendant of itself).”

Example:

Example 1:

Input: 
root = [6,2,8,0,4,7,9,null,null,3,5], p = 2, q = 8
Output: 6

Explanation:

Lowest Common Ancestor of a Binary Search Tree Leetcode SolutionPin

The LCA of nodes 2 and 8 is 6.

Example 2:

Input: 
root = [6,2,8,0,4,7,9,null,null,3,5], p = 2, q = 4
Output: 2

Explanation:

Lowest Common Ancestor of a Binary Search Tree Leetcode SolutionPin

The LCA of nodes 2 and 4 is 2 since a node can be a descendant of itself according to the LCA definition.

Approach:

Idea:

Iterate in BST

  1. Calculate the maximum between the value of node p and node q and store the value in maxi, and in the same way, calculate the minimum between the value of node p and node q and store the value in mini.
  2. We keep iterating root in BST and check :
    1. If  the value of root node > maxi then both node p and q belong to the left subtree, go to the left of the tree.
    2. If  the value of root node< mini then both node p and q belong to the right subtree, go to the right of the tree.
    3. Now, mini <= the value of root node <= maxi the current root is the LCA between q and p.

case1Pin

case2Pin   case3Pin

Code:

C++ Program of  Lowest Common Ancestor of a Binary Search Tree:

class Solution {
public:
    TreeNode* lowestCommonAncestor(TreeNode* root, TreeNode* p, TreeNode* q) {
        int mini = min(p->val, q->val);
        int maxi = max(p->val, q->val);
        while (root != nullptr) {
            if (root->val > maxi)
                root = root->left;
            else if (root->val < mini)
                root = root->right;
            else 
                return root;
        }
        return nullptr;
        
    }
};

Java Program of  Lowest Common Ancestor of a Binary Search Tree:

class Solution {
    public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
        int mini = Math.min(p.val, q.val);
        int maxi = Math.max(p.val, q.val);
        while (root != null) {
            if (root.val > maxi)
                root = root.left;
            else if (root.val < mini)
                root = root.right;
            else 
                return root;
        }
        return null;
    }
}

 

Complexity Analysis for Lowest Common Ancestor of a Binary Search Tree Leetcode Solution:

Time Complexity:

The Time Complexity of the code is O(H), where H is the height of the Binary Tree.

Space Complexity:

The Space Complexity of the code is O(1) because we don’t need any extra space to solve this problem.

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578Implementation of Deque using circular array207
579Number of Provinces Leetcode Solution207
580Minimum number of subsets with distinct elements207
581Trapping Rain Water LeetCode Solution206
582Find Words That Can Be Formed by Characters Leetcode Solution206
583Frog Jump Leetcode Solution206
584Find if an Expression has Duplicate Parenthesis or Not206
585Maximum path sum in a triangle206
586Shortest Path in a Grid with Obstacles Elimination LeetCode Solution206
587Decode Ways206
588Rotate Image LeetCode Solution205
589Remove All Occurrences of a Substring LeetCode Solution205
590First negative integer in every window of size k205
591Relative Sort Array Leetcode Solution205
592Integer to Roman205
593Build Array From Permutation Leetcode Solution205
594Combinations Leetcode Solution204
595Minimum Operations to convert X to Y204
596Delete consecutive same words in a sequence204
597Maximum difference between first and last indexes of an element in array204
598LRU Cache LeetCode Solution204
599Longest Increasing Subsequence204
60001 Matrix LeetCode Solution204
601Word Pattern203
602Minimum number of distinct elements after removing m items203
603Maximum Number of Occurrences of a Substring Leetcode Solution203
604Island Perimeter Leetcode Solution203
605Count all subsequences having product less than K203
606Smallest Good Base203
607Sieve of Eratosthenes203
608Sort Characters By Frequency LeetCode Solution203
609Iterative Method to find Height of Binary Tree203
610Find minimum difference between any two elements202
611Find the smallest positive integer value that cannot be represented as sum of any subset of a given array202
612Assign Cookies Leetcode Solution202
613Remove Linked List Elements Leetcode Solution202
614XOR Operation in an Array Leetcode Solution202
615Non-overlapping sum of two sets201
616Insert Interval Leetcode Solution201
617Rotate List Leetcode Solution201
618Minimum insertions to form a palindrome with permutations allowed201
619GCD Of Two Numbers201
620Stone Game LeetCode201
621Bubble sort using two Stacks201
622Reverse a stack without using extra space in O(n)201
623Convert Sorted Array to Binary Search Tree Leetcode Solution201
624Same Tree LeetCode Solution200
625Sum of f(a[i], a[j]) over all pairs in an array of n integers200
626Applications of Breadth First Search and Depth First Search200
627Tracking current Maximum Element in a Stack200
628The Knapsack Problem200
629Isomorphic Strings199
630Permutation in String Leetcode Solution199
631Find Largest d in Array such that a + b + c = d199
632Maximum Number of Chocolates to be Distributed Equally Among k Students199
633Unique Binary Search Trees199
634Longest Increasing Path in a Matrix LeetCode Solution199
635Defanging an IP Address Leetcode Solution199
636Count Good Nodes in Binary Tree Leetcode Solution199
637Reorganize String199
638Find the Duplicate Number LeetCode Solution199
639K Empty Slots198
640Printing brackets in Matrix Chain Multiplication Problem198
641Optimal Account Balancing LeetCode Solution198
642First Unique Character in a String LeetCode Solution198
643How to Create Mergable Stack?198
644Distance Between Bus Stops Leetcode Solution198
645License Key Formatting Leetcode Solution198
646Employee Free Time LeetCode Solution197
647Form minimum number from given sequence197
648Letter Combinations of a Phone Number197
649Minimum Depth of Binary Tree Leetcode Solution197
650Minimum Number of Steps to Make Two Strings Anagram Leetcode Solutions196
651Replace Elements with Greatest Element on Right Side Leetcode Solution196
652Find pairs with given sum such that elements of pair are in different rows196
653Convert an array to reduced form196
654Find Pair with Greatest Product in Array195
655Sort Array By Parity LeetCode Solution195
656Painting Fence Algorithm195
657Convert a Number to Hexadecimal Leetcode Solution195
658Strobogrammatic Number LeetCode Solution195
659Merge Two Balanced Binary Search Trees195
660Check If It Is a Straight Line Leetcode Solution195
661Word Wrap Problem195
662Reducing Dishes LeetCode Solution195
663Maximum Consecutive Numbers Present in an Array195
664Robot Room Cleaner Leetcode Solution195
665House Robber195
666Kth Missing Positive Number Leetcode Solution194
667Queries for counts of array elements with values in given range194
668Moving Average from Data Stream Leetcode Solution194
669K Empty Slots LeetCode194
670Longest Substring with At Most K Distinct Characters LeetCode Solution194
671Partition Labels LeetCode Solution194
672Segregate 0s and 1s in an Array194
673Largest subarray with equal number of 0s and 1s194
674Find Maximum Level sum in Binary Tree193
675Coin Change Problem193
676Valid Palindrome II Leetcode Solution193
677Reservoir Sampling193
678Sum of All Odd Length Subarrays Leetcode Solution193
679Maximum Product of Two Elements in an Array Leetcode Solution193
680Longest Substring with At Least K Repeating Characters LeetCode Solution193
681Find the node with minimum value in a Binary Search Tree193
682String to Integer (atoi) LeetCode Solution193
683Dynamic Programming Basics192
684Partition Array Into Three Parts With Equal Sum Leetcode Solution192
685Longest Span with same Sum in two Binary arrays192
686Distance of nearest cell having 1 in a binary matrix192
687Best Time to Buy and Sell Stock with Cooldown Leetcode Solution192
688Flipping an Image LeetCode Solution192
689Power of Four Leetcode Solution192
690Valid Palindrome192
691Find the Distance Value Between Two Arrays Leetcode Solution192
692Print the Fibonacci numbers in reverse order192
693Find unique character in a string191
694Remove Invalid Parentheses Leetcode Solution191
695Find Leaves of Binary Tree LeetCode Solution191
696Check If Two String Arrays are Equivalent Leetcode Solution191
697String Compression LeetCode Solution191
698Find the Smallest Divisor given a Threshold Leetcode Solution191
699To Lower Case Leetcode Solution190
700Find the largest multiple of 3190
701Binary Tree Maximum Path Sum LeetCode Solution190
702Numbers with prime frequencies greater than or equal to k190
703Number of Dice Rolls With Target Sum LeetCode Solution190
704Path With Maximum Minimum Value LeetCode Solution190
705Generate all possible sorted arrays from alternate elements of two given sorted arrays190
706Inorder Successor of a node in Binary Tree190
707Wiggle Sort190
708Unique Paths II Leetcode Solution190
709Reverse Only Letters LeetCode Solution190
710Find whether an array is subset of another array189
711Maximum Number of Coins You Can Get Leetcode Solution189
712Lucky Numbers in a Matrix Leetcode Solution189
713Factorial Trailing Zeroes Leetcode Solution189
714Edit Distance LeetCode Solution189
715Sort Array by Increasing Frequency Leetcode Solution189
716Increasing Decreasing String Leetcode Solution189
717Rearrange an array in order – smallest, largest, 2nd smallest, 2nd largest189
718Stack Permutations (Check if an array is stack permutation of other)189
719Subset Sum Leetcode189
720Delete Nth node from the end of the given linked list189
721Permutation Sequence LeetCode Solution188
722Bulb Switcher LeetCode Solution188
723Populating Next Right Pointers in Each Node188
724k-th missing element in increasing sequence which is not present in a given sequence188
725Merge Two Binary Trees LeetCode Solution188
726Reversing a Queue using Recursion188
727Non-decreasing Array LeetCode Solution188
728Snakes and Ladders LeetCode Solution188
729Recover Binary Search Tree188
730Race Car LeetCode Solution188
731Perform String Shifts Leetcode188
732Find if Path Exists in Graph Leetcode Solution188
733Count quadruples from four sorted arrays whose sum is equal to a given value x188
734BFS vs DFS for Binary Tree188
735Valid Perfect Square Leetcode Solution187
736Majority Element II Leetcode Solution187
737Remove brackets from an algebraic string containing + and – operators187
738Evaluate Reverse Polish Notation LeetCode Solution187
739Binary Tree Zigzag Level Order Traversal LeetCode Solution187
740Find Maximum Depth of Nested Parenthesis in a String187
741Maximum 69 Number Leetcode Solution187
742Ugly Number Leetcode Solution187
743Keyboard Row Leetcode Solution186
744Minimum Cost For Tickets Leetcode Solution186
745Base 7 Leetcode Solution186
746Number of NGEs to the Right186
747Print a Binary Tree in Vertical Order186
748Tiling Problem186
749Word Pattern LeetCode Solution186
750Student Attendance Record I Leetcode Solution186
751Maximum Length of a Concatenated String with Unique Characters Leetcode Solution186
752Best Meeting Point LeetCode Solution186
753Merge Sorted Array LeetCode Solution186
754String comparison containing wildcards186
755Find All Possible Recipes from Given Supplies LeetCode Solution185
756Finding K closest element185
757Morris Traversal185
758Find Median from Data Stream LeetCode Solution185
759Add and Search Word – Data structure design LeetCode185
760Elements to be added so that all elements of a range are present in array185
761Split a String in Balanced Strings Leetcode Solution185
762N-Queens LeetCode Solution185
763Growable array based stack185
764Valid Number185
765Program for Bridge and Torch problem185
766Check if Two Expressions With Brackets are Same185
767Restore IP Addresses Leetcode Solution185
768Rank Transform of an Array Leetcode Solution185
769Maximum Product of Three Numbers LeetCode Solution185
770Symmetric Tree Leetcode Solution185
771Binary Tree zigzag level order Traversal185
772Hamming Distance Leetcode Solution184
773Construct BST from given Preorder Traversal184
774Priority Queue using doubly linked list184
775Partition to K Equal Sum Subsets Leetcode Solution184
776Brick Wall LeetCode Solution184
777Check If Array Pairs Are Divisible by k LeetCode Solution184
778Special Array With X Elements Greater Than or Equal X Leetcode Solution184
779Number of Days Between Two Dates LeetCode Solution184
780Maximum Profit in Job Scheduling Leetcode Solution184
781Regular Expression Matching184
782Binomial Coefficient184
783Find All Duplicates in an Array LeetCode Solution184
784Top K Frequent Words LeetCode Solution183
785Sorted Linked List to Balanced BST183
786Minimum Distance Between BST Nodes Leetcode Solution183
787Decompress Run-Length Encoded List Leetcode Solution183
788Minimum sum of multiplications of n numbers183
789Minimize Maximum Pair Sum in Array LeetCode Solution183
790Largest Rectangle in Histogram LeetCode Solution183
791Jump Game183
792Merge K Sorted Linked Lists183
793Search in a Binary Search Tree Leetcode Solution183
794Check for Palindrome after every character replacement Query183
795Invert Binary Tree LeetCode Solution182
796Kth ancestor of a node in binary tree182
797One Edit Distance LeetCode Solution182
798Form Minimum Number From Given Sequence182
799Total Numbers With no Repeated Digits in a Range182
800Nearest Exit from Entrance in Maze LeetCode Solution182
801Maximum Difference Between Increasing Elements LeetCode Solution182
802Minimum Height Trees182
803Largest rectangular sub-matrix whose sum is 0182
804Maximum Depth of N-ary Tree Leetcode Solution182
805Sort an array according to the order defined by another array182
806Queue based approach for first non-repeating character in a stream181
807Final Prices With a Special Discount in a Shop Leetcode Solution181
808Minimum Time Visiting All Points Leetcode Solution181
809Number of Islands II LeetCode Solution181
810Linked List Cycle181
811Circular Queue181
812Identify and Mark Unmatched Parenthesis in an Expression181
813Balanced Expression with Replacement181
814Remove Nth Node From End of List Leetcode Solution181
815Given an Array of Pairs Find all Symmetric Pairs in it180
816Transpose Graph180
817Maximum Nesting Depth of the Parentheses Leetcode Solution180
818Relative Ranks Leetcode Solution180
819Nested List Weight Sum II LeetCode Solution180
820Repeated Substring Pattern LeetCode Solution180
821Diagonal Traversal of Binary Tree180
822Longest Subarray Having Count of 1s One More than Count of 0s180
823Count items common to both the lists but with different prices180
824Minimum time required to rot all oranges180
825Minimum Number of Taps to Open to Water a Garden LeetCode Solution179
826Minimum Swaps to Make Strings Equal Leetcode Solution179
827Search a 2D Matrix II Leetcode Solution179
828Crawler Log Folder Leetcode Solution179
829Deletion in a Binary Tree179
830Clone Graph LeetCode Solution178
831Minimum Jumps to Reach Home LeetCode Solution178
832Permutation Coefficient178
833LCS (Longest Common Subsequence) of three strings178
834Subarray Product Less Than K LeetCode Solution178
835Sort Array By Parity II Leetcode Solution178
836Make Two Arrays Equal by Reversing Sub-arrays Leetcode Solution178
837Subsequence of Size K With the Largest Even Sum LeetCode Solution178
838Number Complement Leetcode Solution178
839Course Schedule II – LeetCode178
840Split Array Into Consecutive Subsequences178
841Reorder Data in Log Files LeetCode Solution178
842Daily Temperatures Leetcode Solution178
843Check if an Array is Stack Sortable177
844Last Stone Weight II LeetCode Solution177
845A Space Optimized DP solution for 0-1 Knapsack Problem177
846Insert Delete GetRandom177
847Missing Element in Sorted Array LeetCode Solution177
848Sliding Window Maximum177
849Distinct adjacent elements in an array177
850Find all permuted rows of a given row in a matrix177
851Binary Search Tree Search and Insertion177
852Lemonade Change Leetcode Solution177
853Design Browser History LeetCode Solution177
854Check if stack elements are pairwise consecutive177
855Find Maximum Sum Possible Equal Sum of Three Stacks177
856Iterative Preorder Traversal177
857Subset with sum divisible by m176
858Minimum number of jumps to reach end176
859Valid Parentheses Leetcode Solution176
860Count Distinct Elements in Every Window of Size K176
861Tree Traversal (Preorder, Inorder & Postorder)176
862Guess Number Higher or Lower LeetCode Solution176
863Matrix Chain Multiplication176
864Path with maximum average value176
865Check if a given array can represent Preorder Traversal of Binary Search Tree176
866Sorted Array to Balanced BST175
867Dividing Array into Pairs With Sum Divisible by K175
868Union and Intersection of two Linked Lists175
869Remove Duplicates from Sorted List LeetCode Solution175
870Minimum Sum Path in a Triangle175
871Alien Dictionary LeetCode Solution175
872Remove Duplicates from Sorted List II175
873Interval Tree175
874Can Place Flowers LeetCode Solution175
875Partition List Leetcode Solution175
876Design a Stack With Increment Operation Leetcode Solution175
877Minimum swaps to make sequences increasing175
878An Interesting Method to generate Binary Numbers from 1 to n175
879Convert BST to Min Heap175
880Get Maximum in Generated Array Leetcode Solution175
881Find the subarray with least average175
882Number of Distinct Islands Leetcode Solution174
883Infix to Postfix174
884Find the Only Repetitive Element Between 1 to N-1174
885Level order Traversal in Spiral Form174
886Spiral Matrix II Leetcode Solution174
887Sort Colors174
888Brightest Position on Street LeetCode Solution174
889Count ways to reach the nth stair using step 1, 2 or 3174
890Sequences of given length where every element is more than or equal to twice of previous174
891GCDs of given index ranges in an array174
892Minesweeper LeetCode Solution174
893Check whether a given Binary Tree is Complete or not174
894Sum of nearest smaller and greater number173
895Median of Two Sorted Arrays173
896Water Bottles Leetcode Solution173
897Diagonal Traverse LeetCode Solution173
898Rearrange Array such that arr[i] >= arr[j] if i is even and arr[i] <= arr[j] if i is odd and j < i173
899Friends Pairing Problem173
900Pattern Occurrences using Stack173
901Find distance between two nodes of a Binary Tree173
902Maximum size subarray sum equals k173
903Find all triplets with zero sum173
904Least Number of Unique Integers after K Removals Leetcode Solution173
905Range sum queries without updates173
906Guess Number Higher or Lower II173
907Maximum Score After Splitting a String Leetcode Solution173
908Insert into a Binary Search Tree Leetcode Solution172
909Lexicographical Numbers Leetcode Solution172
910Iterative Postorder Traversal Using Two Stacks172
911Best Time to Buy and Sell Stock with Transaction Fee Leetcode Solution172
912Time Based Key-Value Store LeetCode Solution172
913Range LCM Queries172
914Delete And Earn172
915Check if any two intervals overlap among a given set of intervals172
916Shortest Word Distance Leetcode Solution172
917Set Matrix Zeroes Leetcode Solution172
918Diagonal Traversal LeetCode Solution171
919Averages of Levels in Binary Tree171
920Difference Array | Range update query in O(1)171
921Count Negative Numbers in a Sorted Matrix LeetCode Solution171
922Robot Bounded In Circle LeetCode Solution171
923All Unique Triplets that Sum up to a Given Value171
924A program to check if a binary tree is BST or not171
925Alien Dictionary171
926Destination City Leetcode Solution171
927Rearrange an Array Such that arr[i] is equal to i171
928My Calendar I LeetCode Solution170
929Construct the Rectangle Leetcode Solution170
930Binary Tree Longest Consecutive Sequence LeetCode Solution170
931Find Common Characters Leetcode Solution170
932Product of Array Except Self LeetCode Solution170
933Count Submatrices With All Ones LeetCode Solution170
934Special Positions in a Binary Matrix Leetcode Solution170
935K’th Largest Element in BST when modification to BST is not allowed170
936Spiral Matrix III LeetCode Solution170
937Check if the given array can represent Level Order Traversal of Binary Search Tree170
938Construct Complete Binary Tree from its Linked List Representation170
939Rearrange Spaces Between Words Leetcode Solution170
940Three way partitioning of an array around a given range170
941Count Subarrays with Same Even and Odd Elements169
942Queue using Stacks169
943Intersection of Two Linked Lists LeetCode Solution169
944Trim a Binary Search Tree169
945Minimum Height Trees LeetCode Solution169
946Number of Equivalent Domino Pairs Leetcode Solution169
947Binary array after M range toggle operations169
948Vertical sum in a given binary tree169
949Maximum Frequency Stack Leetcode Solution169
950Merge Two Sorted Lists Leetcode169
951Three Consecutive Odds Leetcode Solution169
952Convert Sorted List to Binary Search Tree169
953Palindrome Partitioning Leetcode Solution169
954Word Break168
955Analyze User Website Visit Pattern LeetCode Solution168
956Remove Duplicates from Sorted List II LeetCode Solution168
957Strongly Connected Component168
958BFS for Disconnected Graph168
959Largest area rectangular sub-matrix with equal number of 1’s and 0’s168
9603 Sum167
961Longest Palindromic Subsequence167
962Construct BST from its given Level Order Traversal167
963Create Maximum Number167
964Sign of the Product of an Array LeetCode Solution167
965Count Primes in Ranges167
966Kth Smallest Element in a BST Leetcode Solution167
967Climbing stairs167
9684Sum167
969Queries for GCD of all numbers of an array except elements in a given range167
970Maximum Product Subarray167
971Reverse Nodes in K-Group166
972Maximize Sum of Array after K Negations Leetcode Solution166
973Number of palindromic paths in a matrix166
974Count pair with Given Sum166
975Stone Game II Leetcode166
976Unique Paths II166
977Count subarrays where second highest lie before highest166
978Depth First Search (DFS) for a Graph166
979Symmetric Tree166
980Longest subsequence such that difference between adjacents is one166
981Combination Sum IV LeetCode Solution166
982Merging Intervals166
983Breadth First Search (BFS) for a Graph165
984Serialize and Deserialize Binary Tree165
985Design Hit Counter LeetCode Solution165
986Print Fibonacci sequence using 2 variables165
987Find Maximum of Minimum for Every Window Size in a Given Array165
988Longest Nice Substring LeetCode Solution165
989Maximum Subarray Sum Excluding Certain Elements165
990Largest Number Leetcode Solution165
991The Maze III LeetCode Solution165
992Find the First Circular Tour that visits all the Petrol Pumps164
993Binary Search Tree Delete Operation164
994Valid Boomerang Leetcode Solution164
995String Matching in an Array Leetcode Solution164
996Maximum Product of Indexes of Next Greater on Left and Right164
997Asteroid Collision LeetCode Solution164
998Scramble String LeetCode Solution164
999Can Make Arithmetic Progression From Sequence Leetcode Solution164
1000Find number of pairs in an array such that their XOR is 0164
1001Maximum Length of Repeated Subarray164
1002Count pairs from two sorted arrays whose sum is equal to a given value x163
1003Palindrome Partitioning163
1004Next Permutation Leetcode Solution163
1005Graph Valid Tree LeetCode Solution163
1006Consecutive Characters LeetCode Solution163
1007Kth Smallest Element in a Sorted Matrix LeetCode Solution163
1008K Closest Points to Origin Leetcode Solution163
1009K maximum sums of overlapping contiguous sub-arrays163
1010Height of a generic tree from parent array163
1011Minimum Index Sum of Two Lists162
1012Maximum Sum of 3 Non-Overlapping Subarrays162
1013Shortest Completing Word Leetcode Solution162
1014Length of Longest Fibonacci Subsequence162
1015Maximum Number of Ways to Partition an Array LeetCode Solution162
1016Collect maximum points in a grid using two traversals162
1017The Painter’s Partition Problem162
1018Balanced Binary Tree162
1019Find the Difference Leetcode Solution162
1020Decrypt String from Alphabet to Integer Mapping Leetcode Solution162
1021Invalid Transactions LeetCode Solution162
1022Validate Binary Search Tree162
1023Maximum difference between frequency of two elements such that element having greater frequency is also greater162
1024Level Order Traversal of Binary Tree162
1025Shuffle 2n integers as a1-b1-a2-b2-a3-b3-..bn without using extra space162
1026Find postorder traversal of BST from preorder traversal162
1027Print Next Greater Number of Q queries161
1028Newman-Conway Sequence161
1029Merge Sort161
1030Generate Parentheses Leetcode Solution161
1031Remove Duplicates from Sorted Array II Leetcode Solution161
1032Find Duplicate Subtrees161
1033Largest divisible pairs subset161
1034Available Captures for Rook Leetcode Solution161
1035Segment Tree161
1036Rearrange an array such that ‘arr[j]’ becomes ‘i’ if ‘arr[i]’ is ‘j’161
1037Maximum length subsequence with difference between adjacent elements as either 0 or 1161
1038Move all negative elements to end in order with extra space allowed161
1039Custom Sort String Leetcode Solution160
1040Make The String Great Leetcode Solution160
1041Number Of Longest Increasing Subsequence160
1042Advantages of BST over Hash Table160
1043Next Greater Element III LeetCode Solution160
1044First missing positive160
1045Check If a Word Occurs As a Prefix of Any Word in a Sentence Leetcode Solution160
1046Insertion in a Binary Tree160
1047Construct Binary Tree from given Parent Array representation160
1048Binary Search Tree160
1049Boolean Parenthesization Problem160
1050Construction of Longest Increasing Subsequence (N log N)160
1051Find a Peak Element II LeetCode Solution160
1052Largest Substring Between Two Equal Characters Leetcode Solution160
1053Print Right View of a Binary Tree159
1054Rearrange array such that even positioned are greater than odd159
1055Count minimum steps to get the given desired array159
1056Bitwise AND of Numbers Range LeetCode Solution159
1057Compute nCr % p159
1058Iterative Depth First Traversal of Graph159
1059Boundary Traversal of binary tree159
1060Friends Of Appropriate Ages LeetCode Solution159
1061Build an Array With Stack Operations Leetcode Solution158
1062Determine Whether Matrix Can Be Obtained By Rotation LeetCode Solution158
1063Double the first element and move zero to end158
1064Kill Process LeetCode Solution158
1065Subarrays with K Different Integers Leetcode Solution158
1066Maximum subsequence sum such that no three are consecutive158
1067Path Sum II LeetCode Solution158
1068Rearrange array such that even index elements are smaller and odd index elements are greater158
1069Minimum Size Subarray Sum158
1070Largest BST Subtree LeetCode Solution158
1071Level order traversal using two Queues157
1072Regular Expression Matching Regular Expression Matching LeetCode Solution157
1073Employee Importance LeetCode Solution157
1074Recover Binary Search Tree Leetcode Solution157
1075Morris Inorder Traversal157
1076Defanging an IP Address LeetCode Solution157
1077Remove Palindromic Subsequences Leetcode Solution157
1078Find Peak Element157
1079Add two numbers157
1080Lowest Common Ancestor156
1081Find maximum difference between nearest left and right smaller elements156
1082Partition Equal Subset Sum156
1083Implement Trie (Prefix Tree) Leetcode Solution156
1084Ugly Numbers156
1085Palindrome Permutation LeetCode Solution156
1086Smallest Common Region Leetcode Solution156
1087Maximum weight transformation of a given string156
1088Ugly Number II LeetCode Solution156
1089Number of Closed Islands Leetcode Solution155
1090Binary Tree Right Side View LeetCode Solution155
1091Maximize Distance to Closest Person LeetCode Solution155
1092Bus Routes Leetcode Solution155
1093Remove duplicates from sorted array155
1094Increasing Triplet Subsequence LeetCode Solution155
1095Longest Bitonic Subsequence155
1096Super Ugly Number155
1097Palindromic Substrings Leetcode Solution155
1098Find whether a subarray is in form of a mountain or not154
1099Print all triplets in sorted array that form AP154
1100Populating Next Right Pointers in Each Node Leetcode Solution154
1101Sum of Even Numbers After Queries154
1102Path Sum154
1103Valid Tic-Tac-Toe State LeetCode Solution154
1104Construct Binary Tree from Preorder and Postorder Traversal LeetCode Solution154
1105Binary Tree Data Structure153
1106Find the minimum distance between two numbers153
1107Find Three Element From Different Three Arrays Such That a + b + c = sum153
1108Thousand Separator Leetcode Solution153
1109Divisible Pairs Counting153
1110Reformat The String Leetcode Solution153
1111Moser-de Bruijn Sequence153
1112Number of siblings of a given Node in n-ary Tree153
1113Search in Sorted Rotated Array153
1114Iterative method to find ancestors of a given binary tree153
1115Kth Smallest Product of Two Sorted Arrays LeetCode Solution152
1116Cells with Odd Values in a Matrix LeetCode Solution152
1117Level of Each node in a Tree from source node152
1118Search Insert Position152
1119Number of Students Doing Homework at a Given Time Leetcode Solution152
1120Count Largest Group Leetcode Solution152
1121Day of the Year Leetcode Solution152
1122Mean of Array After Removing Some Elements Leetcode Solution152
1123Find Smallest Range Containing Elements from k Lists152
1124Root to Leaf path with target sum Leetcode Solutions151
1125Distinct Subsequences151
1126Products of ranges in an array151
1127Clone a Binary Tree with Random Pointers151
1128Serialize and Deserialize Binary Tree LeetCode Solution151
1129Longest Increasing Consecutive Subsequence151
1130Find maximum length Snake sequence150
1131Minimum Absolute Difference in BST Leetcode Solution150
1132Maximum Product of Splitted Binary Tree LeetCode Solution150
1133Prime Palindrome LeetCode Solution150
1134Compare Strings by Frequency of the Smallest Character Leetcode Solution150
1135Third Maximum Number Leetcode Solution150
1136Constant time range add operation on an array150
1137Topological Sorting150
1138Find Two Non-overlapping Sub-arrays Each With Target Sum LeetCode Solution150
1139Maximum Depth Of Binary Tree149
1140Bottom View of a Binary Tree149
1141Longest Repeated Subsequence149
1142Minimum sum of squares of character counts in a given string after removing k characters149
1143Maximum Product Subarray149
1144Construct K Palindrome Strings LeetCode Solution149
1145Queries for Number of Distinct Elements in a Subarray149
1146Convert BST into a Min-Heap without using array149
1147Search an Element in Sorted Rotated Array148
1148Web Crawler LeetCode Solution148
1149Priority Queue148
1150Rotate Array148
1151Minimum Moves to Equal Array Elements LeetCode Solution148
1152Minimum Score Triangulation of Polygon Leetcode Solution148
1153Longest Subarray of 1’s After Deleting One Element LeetCode Solution148
1154Diameter of N-Ary Tree LeetCode Solution148
1155Count even length binary sequences with same sum of first and second half bits148
1156Print modified array after executing the commands of addition and subtraction148
1157Write Code to Determine if Two Trees are Identical148
1158Reformat Date LeetCode Solution148
1159Closest Leaf in a Binary Tree LeetCode Solution147
1160Golomb sequence147
1161Delete Nodes and Return Forest Leetcode Solution147
1162Find Largest Value in Each Tree Row LeetCode Solution147
1163Find a sorted subsequence of size 3 in linear time147
1164Closest Binary Search Tree Value Leetcode Solution147
1165Subset Sum Problem in O(sum) space147
1166Cutting a Rod147
1167Matchsticks to Square Leetcode Solution146
1168Minimum Cost to Move Chips to The Same Position LeetCode Solution146
1169Search Suggestions System LeetCode Solution146
1170Maximize sum of consecutive differences in a circular array146
1171Contiguous Array LeetCode Solution146
1172Given a binary tree, how do you remove all the half nodes?146
1173Kth Smallest Number in Multiplication Table Leetcode Solution146
1174Swap Nodes In Pairs146
1175Count Pairs Whose Products Exist in Array145
1176Maximum sum of a path in a Right Number Triangle145
1177Minimum Sideway Jumps LeetCode Solution145
1178K’th Largest element in BST using constant extra space145
1179Transform a BST to Greater sum Tree145
1180Red-Black Tree Introduction145
1181Minimum Swaps To Make Sequences Increasing LeetCode Solution145
1182Possible Bipartition LeetCode Solution145
1183Decision Tree145
1184Merge two BSTs with limited extra space144
1185Decrease Elements To Make Array Zigzag LeetCode Solution144
1186Binary Tree to Binary Search Tree Conversion144
1187Find the smallest binary digit multiple of given number144
1188Remove Max Number of Edges to Keep Graph Fully Traversable Leetcode Solution144
1189Check Array Formation Through Concatenation Leetcode Solution144
1190Path Crossing Leetcode Solution144
1191Replace two consecutive equal values with one greater144
1192Maximum Value at a Given Index in a Bounded Array LeetCode Solution144
1193Maximum Binary Tree144
1194First Bad Version144
1195Reverse a Path in BST using Queue144
1196Sum of Left Leaves LeetCode Solution144
1197Valid Triangle Number143
1198Maximum sum of pairs with specific difference143
1199Maximum number of segments of lengths a, b and c143
1200Print n terms of Newman-Conway Sequence143
1201Perfect Squares LeetCode Solution143
1202Factorial Trailing Zeroes LeetCode Solution143
1203Convert Integer to the Sum of Two No-Zero Integers Leetcode Solution143
1204Number of Orders in the Backlog Leetcode Solution143
1205Convert Sorted Array to Binary Search Tree LeetCode Solutions142
1206Divide Two Integers Leetcode Solution142
1207Sliding Window Median Leetcode Solution142
1208Concatenation of Array LeetCode Solution142
1209Queue Reconstruction by Height142
1210Maximum sum bitonic subarray142
1211Integer Break LeetCode Solution141
1212How to print maximum number of A’s using given four keys141
1213New 21 Game141
1214Valid Perfect Square LeetCode Solution141
1215Swapping Nodes in a Linked List Leetcode Solution141
1216Guess The Word140
1217Kth Smallest Element in a BST140
1218Lowest Common Ancestor of a Binary Tree Leetcode Solution140
1219Champagne Tower LeetCode Solution140
1220Array Queries for multiply replacements and product140
1221Lowest Common Ancestor in Binary Search Tree140
1222Graph and its representation140
1223Queries on Probability of Even or Odd Number in given Ranges140
1224Moving Stones Until Consecutive Leetcode Solution139
1225Find minimum number of merge operations to make an array palindrome139
1226Flatten 2D Vector LeetCode Solution139
1227Check if all levels of two Binary Tree are anagrams or not139
1228Longest Common Prefix Using Word by Word Matching139
1229Merge k Sorted Lists Leetcode Solution139
1230Range Sum Query using Sparse Table138
1231Filter Restaurants by Vegan-Friendly, Price and Distance Leetcode Solution138
1232Mean of range in array138
1233Find Minimum in Rotated Sorted Array II LeetCode Solution138
1234Maximum Array from Two given Arrays Keeping Order Same138
1235Maximize Elements Using Another Array137
1236Range Queries for Longest Correct Bracket Subsequence137
1237Missing Number137
1238Bold Words in String LeetCode Solution137
1239LRU Cache Leetcode Solution137
1240BST to a Tree with Sum of all Smaller Keys137
1241Maximum Sum Increasing Subsequence137
1242Design Skiplist LeetCode Solution137
1243Print modified array after multiple array range increment operations137
1244Contiguous Array137
1245Min Cost Climbing Stairs LeetCode Solution136
1246Minimum Remove to Make Valid Parentheses LeetCode Solution136
1247Count Subsets Having Distinct Even Numbers136
1248Write a function to get the intersection point of two Linked Lists136
1249Maximum Product Subarray136
1250Parallel Courses II LeetCode Solution136
1251The kth Factor of n Leetcode Solution136
1252Largest Plus Sign Leetcode Solution136
1253Graph Cloning135
1254Power of Two135
1255Check in binary array the number represented by a subarray is odd or even135
1256Find k-th smallest element in BST (Order Statistics in BST)135
1257Check if each internal node of a BST has exactly one child134
1258Arithmetic Slices II – Subsequence LeetCode Solution134
1259Different Ways to Add Parentheses Leetcode Solution134
1260Verify Preorder Serialization of a Binary Tree133
1261Check if two nodes are on the same path in a Tree133
1262Image Overlap LeetCode Solution133
1263Minimum Time to Collect All Apples in a Tree LeetCode Solution133
1264Check for Identical BSTs without building the trees133
1265Print Ancestors of a Given Binary Tree Node Without Recursion132
1266Check Completeness of a Binary Tree LeetCode Solution132
1267Symmetric Tree LeetCode Solution Leetcode Solution132
1268Smallest Range II Leetcode Solution132
1269Orderly Queue LeetCode Solution132
1270Koko Eating Bananas LeetCode Solution131
1271Next greater element131
1272Excel Sheet Column Title LeetCode Solution131
1273Arranging Coins Leetcode Solution130
1274Longest Substring Without Repeating Characters Leetcode Solution130
1275Merge Sorted Array129
1276Count and Toggle Queries on a Binary Array129
1277Number of elements less than or equal to a given number in a given subarray129
1278Largest Submatrix With Rearrangements LeetCode Solution128
1279Vertical Order Traversal of Binary Tree LeetCode Solution128
1280Palindrome Number LeetCode Solution127
1281Array Nesting Leetcode Solution127
1282Palindrome Partitioning127
1283Add Two Numbers II Leetcode Solution126
1284Check If a String Can Break Another String Leetcode Solution126
1285Newman–Shanks–Williams prime126
1286Find the Winner of the Circular Game LeetCode Solution125
1287Insert Delete GetRandom O(1) Leetcode Solution125
1288Maximum product of an increasing subsequence125
1289Peeking Iterator LeetCode Solution125
1290Check if X can give change to every person in the Queue125
1291Queries for Decimal Values of Subarrays of a Binary Array125
1292Range Minimum Query (Square Root Decomposition and Sparse Table)124
1293Find maximum average subarray of k length124
1294Encoded String With Shortest Length LeetCode Solution123
1295Number of Subsequences That Satisfy the Given Sum Condition LeetCode solution122
1296Check given array of size n can represent BST of n levels or not122
1297Jump Game IV LeetCode Solution121
1298Continuous Subarray Sum LeetCode Solution121
1299Random Pick Index LeetCode Solution121
1300Minimum Possible Integer After at Most K Adjacent Swaps On Digits LeetCode Solution120
1301Binary Tree to Binary Search Tree Conversion using STL set120
1302Reach a Number LeetCode Solution120
1303Number of indexes with equal elements in given range120
1304Minimum Number of People to Teach LeetCode Solution119
1305Convert a BST to a Binary Tree such that sum of all greater keys is added to every key118
1306Minimum Total Space Wasted With K Resizing Operations LeetCode Solution117
1307Convert to Base -2 LeetCode Solution116
1308Design A Leaderboard Leetcode Solution115
1309Queries on XOR of greatest odd divisor of the range115
1310Design Underground System Leetcode Solution114
1311Shifting Letters LeetCode Solution112
1312Print Maximum Length Chain of Pairs111
1313Detect Capital Leetcode Solution111
1314Minimum Swaps to Group All 1’s Together Leetcode Solution110
1315Top K Frequent Elements LeetCode Solution109
1316Count Sub Islands LeetCode Solution108
1317Minimum Path Sum Leetcode Solution107
1318Odd Even Linked List Leetcode Solution106
1319Substring with Concatenation of All Words Leetcode Solution106
1320Monotonic Array Leetcode Solution105
1321Longest Common Subsequence LeetCode Solution102
1322Binary Tree Inorder Traversal LeetCode Solution101
1323Decode String Leetcode Solution101
1324Maximum Population Year LeetCode Solution100
1325Find the Town Judge LeetCode Solution100
1326Shortest Unsorted Continuous Subarray LeetCode Solution95
1327Best Meeting Point LeetCode Solution94
1328Rectangle Overlap LeetCode Solution94
1329Maximum Population Year LeetCode Solution93
1330Find the Town Judge LeetCode Solution92
1331Insert into a Sorted Circular Linked List LeetCode Solution91
1332Sum Root to Leaf Numbers LeetCode Solution91
1333Flatten Binary Tree to Linked List LeetCode Solution90
1334Design Add and Search Words Data Structure LeetCode Solution90
1335Reveal Cards In Increasing Order Leetcode Solution88
1336Stone Game IV LeetCode Solution88
1337Range Sum Query 2D – Immutable LeetCode Solution87
1338Is Graph Bipartite? LeetCode Solution87
1339Valid Triangle Number LeetCode Solution86
1340Score of Parenthesis LeetCode Solution85
1341Divide Chocolate LeetCode Solution81
1342Step-By-Step Directions From a Binary Tree Node to Another LeetCode Solution75
1343Range Sum of BST LeetCode Solution69
1344Reverse Integer Leetcode Solution66
1345Find K Closest Elements LeetCode Solution64
1346Rotate String LeetCode Solution64
1347Sort Colors LeetCode Solution63
1348Maximum Side Length of a Square with Sum Less than or Equal to Threshold LeetCode Solution61
1349Excel Sheet Column Number LeetCode Solution57
1350Maximum Size Subarray Sum Equals k Leetcode Solution50
1351H-Index Leetcode Solution46
1352Camelcase Matching Leetcode Solution45
1353Valid Anagram Leetcode Solution44
1354Container With Most Water LeetCode Solution43
1355Most Stones Removed with Same Row or Column LeetCode Solution43
1356Group Anagrams LeetCode Solution42
1357Sliding Window Maximum LeetCode Solution42
1358High Five LeetCode Solution41
1359Next Permutation LeetCode Solution41
1360Binary Search LeetCode Solution40
1361Find Peak Element LeetCode Solution40
1362Pairs of Songs With Total Durations Divisible by 60 LeetCode Solution39
1363Paint House LeetCode Solution37
1364Minimum Number of Arrows to Burst Balloons LeetCode Solution36
1365Valid Triangle Number LeetCode Solution36
1366Unique Binary Search Trees LeetCode Solution35
1367Next Greater Element I Leetcode Solution35
1368Isomorphic Strings LeetCode Solution35
1369Flatten Binary Tree to Linked List LeetCode Solution35
1370Group Shifted Strings Leetcode Solution34
1371Sentence Screen Fitting LeetCode Solution33
1372The Number of Weak Characters in the Game LeetCode Solution33
1373Swim in Rising Water LeetCode Solution32
1374Count Good Nodes in Binary Tree LeetCode Solution32
1375Insert Delete GetRandom O(1) – Duplicates allowed LeetCode Solution32
1376Closest Binary Search Tree Value II LeetCode Solution31
1377Peak Index in a Mountain Array LeetCode Solution31
1378Single Element in a Sorted Array LeetCode Solution29
1379Split Linked List in Parts Leetcode Solution27
1380All Possible Full Binary Trees LeetCode Solution27
1381Validate Stack Sequences LeetCode Solution26
1382Minimum Increment to Make Array Unique Leetcode Solution26
1383Max Sum of Two Non-Overlapping Subarrays LeetCode Solution25
1384Find First and Last Position of Element in Sorted Array LeetCode Solution25
1385Lowest Common Ancestor of a Binary Search Tree Leetcode Solution25
1386Greatest Sum Divisible by Three LeetCode Solution24
1387Best Time to Buy and Sell Stock IV LeetCode Solution24
1388Detect Squares LeetCode Solution24
1389Implement strStr() LeetCode Solution23
1390Trapping Rain Water II LeetCode Solution23
1391Stone Game IV LeetCode Solution22
1392Break a Palindrome LeetCode Solution22
1393Implement Rand10() Using Rand7() Leetcode Solution22
1394Fibonacci Number LeetCode Solution20
1395Contains Duplicate LeetCode Solution20
1396Remove All Ones With Row and Column Flips Leetcode Solution19
1397Invert Binary Tree LeetCode Solution19
1398Design Bounded Blocking Queue LeetCode Solution18
1399Reverse Nodes in k-Group LeetCode Solution17
1400Minimum Number of Operations to Move All Balls to Each Box LeetCode Solution16
1401Candy LeetCode Solution14
1402Total Hamming Distance LeetCode Solution14
1403Unique Paths III LeetCode Solution12
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