Fibonacci Number LeetCode Solution


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Problem Statement:

Fibonacci Number LeetCode Solution says that – The Fibonacci numbers, commonly denoted F(n) form a sequence, called the Fibonacci sequence, such that each number is the sum of the two preceding ones, starting from 0 and 1. That is

F(0) = 0, F(1) = 1
F(n) = F(n - 1) + F(n - 2), for n > 1.

Given n, calculate F(n).

Example 1:

Input:

 n = 2

Output:

 1

Explanation:

 F(2) = F(1) + F(0) = 1 + 0 = 1.

Example 2:

Input:

 n = 3

Output:

 2

Explanation:

 F(3) = F(2) + F(1) = 1 + 1 = 2.

Example 3:

Input:

 n = 4

Output:

 3

Explanation:

 F(4) = F(3) + F(2) = 2 + 1 = 3.

 

Constraints:

  • 0 <= n <= 30

ALGORITHM –

The Fibonacci numbers are the numbers in the following integer sequence:

$1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, ……$. We can see the Fibonacci series sequences in the natural world like the sunflower, the nautilus, and the galaxy.

In mathematical terms, the sequence F(n) of Fibonacci numbers is defined by the recurrence relation

F(n)=F(n−1)+F(n−2)

with seed values F(0)=0 and F(1)=1.

The Fibonacci sequence is often used in introductory computer science courses to explain recurrence relations, dynamic programming, and proofs by induction.

IDEA –

  • In order to find Fibonacci Number LeetCode Solution. We will use the concept of Fibonacci. So Fibonacci series generates the subsequent number by adding two previous numbers. The Fibonacci series starts from two numbers − F0 & F1. The initial values of F0 & F1 can be taken 0, 1, or 1, 1
  •                                                                  Fn = Fn-1 + Fn-2

For example,

F5 = 0,1, 1, 2, 3

  Image –

Fibonacci Number LeetCode SolutionPin Fibonacci Number LeetCode SolutionPin

class Solution:
    def fib(self, n: int) -> int:
        if n == 0 or n == 1:
            return n
        
        a = 0
        b = 1
        for i in range(1,n):
            c = a+b
            a = b
            b = c
            
        return b
class Solution 
{
    public int fib(int N)
    {
        if(N <= 1)
            return N;
        
    int a = 0, b = 1;
    
    while(N-- > 1)
    {
      int c = a + b;
      a = b;
      b = c;
    }
        return b;
    }
}

Time Complexity – O(N), As we have traversed only one time.

Space Complexity – O(1), As we haven’t taken any extra space.

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581Trapping Rain Water LeetCode Solution206
5823Sum Closest LeetCode Solution206
583Maximum path sum in a triangle206
584Decode Ways206
585Number of Provinces Leetcode Solution205
586Remove All Occurrences of a Substring LeetCode Solution205
587Build Array From Permutation Leetcode Solution205
588First negative integer in every window of size k205
589Find if an Expression has Duplicate Parenthesis or Not205
590Rotate Image LeetCode Solution205
591Minimum number of subsets with distinct elements205
592Integer to Roman205
593Relative Sort Array Leetcode Solution205
594LRU Cache LeetCode Solution204
59501 Matrix LeetCode Solution204
596Delete consecutive same words in a sequence204
597Minimum Operations to convert X to Y204
598Combinations Leetcode Solution204
599Minimum number of distinct elements after removing m items203
600Sieve of Eratosthenes203
601Maximum difference between first and last indexes of an element in array203
602Smallest Good Base203
603Island Perimeter Leetcode Solution203
604Word Pattern203
605Iterative Method to find Height of Binary Tree203
606Maximum Number of Occurrences of a Substring Leetcode Solution203
607Longest Increasing Subsequence203
608Sort Characters By Frequency LeetCode Solution202
609Assign Cookies Leetcode Solution202
610Count all subsequences having product less than K202
611XOR Operation in an Array Leetcode Solution202
612Find minimum difference between any two elements201
613Non-overlapping sum of two sets201
614Rotate List Leetcode Solution201
615Minimum insertions to form a palindrome with permutations allowed201
616Remove Linked List Elements Leetcode Solution201
617Insert Interval Leetcode Solution201
618Convert Sorted Array to Binary Search Tree Leetcode Solution201
619GCD Of Two Numbers201
620Find the smallest positive integer value that cannot be represented as sum of any subset of a given array201
621Stone Game LeetCode201
622Reverse a stack without using extra space in O(n)200
623Applications of Breadth First Search and Depth First Search200
624The Knapsack Problem200
625Tracking current Maximum Element in a Stack200
626Same Tree LeetCode Solution200
627Sum of f(a[i], a[j]) over all pairs in an array of n integers200
628Permutation in String Leetcode Solution199
629Unique Binary Search Trees199
630Find the Duplicate Number LeetCode Solution199
631Isomorphic Strings199
632Bubble sort using two Stacks199
633Reorganize String199
634Optimal Account Balancing LeetCode Solution198
635Longest Increasing Path in a Matrix LeetCode Solution198
636Printing brackets in Matrix Chain Multiplication Problem198
637Count Good Nodes in Binary Tree Leetcode Solution198
638Maximum Number of Chocolates to be Distributed Equally Among k Students198
639License Key Formatting Leetcode Solution198
640Find Largest d in Array such that a + b + c = d198
641Defanging an IP Address Leetcode Solution198
642K Empty Slots198
643Distance Between Bus Stops Leetcode Solution198
644Form minimum number from given sequence197
645Employee Free Time LeetCode Solution197
646How to Create Mergable Stack?197
647First Unique Character in a String LeetCode Solution197
648Letter Combinations of a Phone Number197
649Minimum Depth of Binary Tree Leetcode Solution196
650Convert an array to reduced form196
651Replace Elements with Greatest Element on Right Side Leetcode Solution196
652Minimum Number of Steps to Make Two Strings Anagram Leetcode Solutions196
653Painting Fence Algorithm195
654Robot Room Cleaner Leetcode Solution195
655Find Pair with Greatest Product in Array195
656Check If It Is a Straight Line Leetcode Solution195
657Reducing Dishes LeetCode Solution195
658House Robber195
659Sort Array By Parity LeetCode Solution195
660Find pairs with given sum such that elements of pair are in different rows195
661Merge Two Balanced Binary Search Trees195
662Strobogrammatic Number LeetCode Solution195
663Word Wrap Problem195
664Segregate 0s and 1s in an Array194
665K Empty Slots LeetCode194
666Largest subarray with equal number of 0s and 1s194
667Queries for counts of array elements with values in given range194
668Kth Missing Positive Number Leetcode Solution194
669Moving Average from Data Stream Leetcode Solution194
670Convert a Number to Hexadecimal Leetcode Solution194
671Maximum Consecutive Numbers Present in an Array194
672Find Maximum Level sum in Binary Tree193
673String to Integer (atoi) LeetCode Solution193
674Longest Substring with At Least K Repeating Characters LeetCode Solution193
675Partition Labels LeetCode Solution193
676Valid Palindrome II Leetcode Solution193
677Maximum Product of Two Elements in an Array Leetcode Solution193
678Power of Four Leetcode Solution192
679Distance of nearest cell having 1 in a binary matrix192
680Longest Substring with At Most K Distinct Characters LeetCode Solution192
681Partition Array Into Three Parts With Equal Sum Leetcode Solution192
682Dynamic Programming Basics192
683Coin Change Problem192
684Print the Fibonacci numbers in reverse order192
685Reservoir Sampling191
686Longest Span with same Sum in two Binary arrays191
687Find the node with minimum value in a Binary Search Tree191
688Valid Palindrome191
689Find unique character in a string191
690Remove Invalid Parentheses Leetcode Solution191
691String Compression LeetCode Solution191
692Find the Distance Value Between Two Arrays Leetcode Solution191
693Best Time to Buy and Sell Stock with Cooldown Leetcode Solution191
694Check If Two String Arrays are Equivalent Leetcode Solution191
695Sum of All Odd Length Subarrays Leetcode Solution191
696Reverse Only Letters LeetCode Solution190
697Number of Dice Rolls With Target Sum LeetCode Solution190
698Path With Maximum Minimum Value LeetCode Solution190
699Find the largest multiple of 3190
700Wiggle Sort190
701Numbers with prime frequencies greater than or equal to k190
702Unique Paths II Leetcode Solution190
703Find the Smallest Divisor given a Threshold Leetcode Solution190
704Generate all possible sorted arrays from alternate elements of two given sorted arrays190
705Inorder Successor of a node in Binary Tree190
706To Lower Case Leetcode Solution190
707Flipping an Image LeetCode Solution190
708Find Leaves of Binary Tree LeetCode Solution190
709Binary Tree Maximum Path Sum LeetCode Solution190
710Maximum Number of Coins You Can Get Leetcode Solution189
711Edit Distance LeetCode Solution189
712Subset Sum Leetcode189
713Stack Permutations (Check if an array is stack permutation of other)189
714Rearrange an array in order – smallest, largest, 2nd smallest, 2nd largest189
715Increasing Decreasing String Leetcode Solution189
716Delete Nth node from the end of the given linked list189
717Factorial Trailing Zeroes Leetcode Solution189
718Non-decreasing Array LeetCode Solution188
719Merge Two Binary Trees LeetCode Solution188
720Race Car LeetCode Solution188
721Sort Array by Increasing Frequency Leetcode Solution188
722Find whether an array is subset of another array188
723Count quadruples from four sorted arrays whose sum is equal to a given value x188
724Bulb Switcher LeetCode Solution188
725Permutation Sequence LeetCode Solution188
726Snakes and Ladders LeetCode Solution188
727Reversing a Queue using Recursion188
728Valid Perfect Square Leetcode Solution187
729Ugly Number Leetcode Solution187
730Binary Tree Zigzag Level Order Traversal LeetCode Solution187
731BFS vs DFS for Binary Tree187
732Perform String Shifts Leetcode187
733Majority Element II Leetcode Solution187
734Lucky Numbers in a Matrix Leetcode Solution187
735Maximum 69 Number Leetcode Solution187
736Populating Next Right Pointers in Each Node187
737Find if Path Exists in Graph Leetcode Solution187
738Find Maximum Depth of Nested Parenthesis in a String187
739String comparison containing wildcards186
740Keyboard Row Leetcode Solution186
741Student Attendance Record I Leetcode Solution186
742Best Meeting Point LeetCode Solution186
743Number of NGEs to the Right186
744Remove brackets from an algebraic string containing + and – operators186
745Tiling Problem186
746Base 7 Leetcode Solution186
747Minimum Cost For Tickets Leetcode Solution186
748Recover Binary Search Tree186
749Merge Sorted Array LeetCode Solution186
750Evaluate Reverse Polish Notation LeetCode Solution186
751Maximum Length of a Concatenated String with Unique Characters Leetcode Solution186
752Restore IP Addresses Leetcode Solution185
753Program for Bridge and Torch problem185
754Find All Possible Recipes from Given Supplies LeetCode Solution185
755Print a Binary Tree in Vertical Order185
756Finding K closest element185
757Morris Traversal185
758Binary Tree zigzag level order Traversal185
759Rank Transform of an Array Leetcode Solution185
760Elements to be added so that all elements of a range are present in array185
761k-th missing element in increasing sequence which is not present in a given sequence185
762Maximum Product of Three Numbers LeetCode Solution185
763Word Pattern LeetCode Solution185
764Valid Number185
765Find Median from Data Stream LeetCode Solution185
766Symmetric Tree Leetcode Solution185
767Split a String in Balanced Strings Leetcode Solution185
768Add and Search Word – Data structure design LeetCode184
769Find All Duplicates in an Array LeetCode Solution184
770Maximum Profit in Job Scheduling Leetcode Solution184
771Partition to K Equal Sum Subsets Leetcode Solution184
772Construct BST from given Preorder Traversal184
773Check if Two Expressions With Brackets are Same184
774N-Queens LeetCode Solution184
775Special Array With X Elements Greater Than or Equal X Leetcode Solution184
776Regular Expression Matching184
777Brick Wall LeetCode Solution184
778Binomial Coefficient184
779Check If Array Pairs Are Divisible by k LeetCode Solution184
780Priority Queue using doubly linked list183
781Sorted Linked List to Balanced BST183
782Minimum Distance Between BST Nodes Leetcode Solution183
783Decompress Run-Length Encoded List Leetcode Solution183
784Hamming Distance Leetcode Solution183
785Growable array based stack183
786Jump Game183
787Search in a Binary Search Tree Leetcode Solution182
788Total Numbers With no Repeated Digits in a Range182
789Kth ancestor of a node in binary tree182
790Merge K Sorted Linked Lists182
791Largest rectangular sub-matrix whose sum is 0182
792Largest Rectangle in Histogram LeetCode Solution182
793Minimize Maximum Pair Sum in Array LeetCode Solution182
794Minimum Height Trees182
795Maximum Depth of N-ary Tree Leetcode Solution182
796Invert Binary Tree LeetCode Solution182
797Sort an array according to the order defined by another array182
798Maximum Difference Between Increasing Elements LeetCode Solution182
799Top K Frequent Words LeetCode Solution182
800Nearest Exit from Entrance in Maze LeetCode Solution182
801Check for Palindrome after every character replacement Query182
802Form Minimum Number From Given Sequence182
803One Edit Distance LeetCode Solution182
804Balanced Expression with Replacement181
805Circular Queue181
806Identify and Mark Unmatched Parenthesis in an Expression181
807Number of Days Between Two Dates LeetCode Solution181
808Minimum sum of multiplications of n numbers181
809Minimum Time Visiting All Points Leetcode Solution181
810Number of Islands II LeetCode Solution181
811Final Prices With a Special Discount in a Shop Leetcode Solution181
812Remove Nth Node From End of List Leetcode Solution181
813Queue based approach for first non-repeating character in a stream180
814Diagonal Traversal of Binary Tree180
815Linked List Cycle180
816Transpose Graph180
817Longest Subarray Having Count of 1s One More than Count of 0s180
818Maximum Nesting Depth of the Parentheses Leetcode Solution180
819Repeated Substring Pattern LeetCode Solution180
820Nested List Weight Sum II LeetCode Solution180
821Relative Ranks Leetcode Solution180
822Search a 2D Matrix II Leetcode Solution179
823Count items common to both the lists but with different prices179
824Deletion in a Binary Tree179
825Minimum time required to rot all oranges179
826Given an Array of Pairs Find all Symmetric Pairs in it179
827Minimum Number of Taps to Open to Water a Garden LeetCode Solution179
828Minimum Swaps to Make Strings Equal Leetcode Solution179
829Crawler Log Folder Leetcode Solution179
830Permutation Coefficient178
831Clone Graph LeetCode Solution178
832Subarray Product Less Than K LeetCode Solution178
833Split Array Into Consecutive Subsequences178
834Number Complement Leetcode Solution178
835Course Schedule II – LeetCode178
836Sort Array By Parity II Leetcode Solution178
837Daily Temperatures Leetcode Solution178
838Binary Search Tree Search and Insertion177
839Find Maximum Sum Possible Equal Sum of Three Stacks177
840Reorder Data in Log Files LeetCode Solution177
841Check if an Array is Stack Sortable177
842A Space Optimized DP solution for 0-1 Knapsack Problem177
843LCS (Longest Common Subsequence) of three strings177
844Minimum Jumps to Reach Home LeetCode Solution177
845Make Two Arrays Equal by Reversing Sub-arrays Leetcode Solution177
846Missing Element in Sorted Array LeetCode Solution177
847Find all permuted rows of a given row in a matrix177
848Subsequence of Size K With the Largest Even Sum LeetCode Solution177
849Distinct adjacent elements in an array177
850Check if stack elements are pairwise consecutive177
851Lemonade Change Leetcode Solution177
852Sliding Window Maximum176
853Design Browser History LeetCode Solution176
854Count Distinct Elements in Every Window of Size K176
855Last Stone Weight II LeetCode Solution176
856Guess Number Higher or Lower LeetCode Solution176
857Minimum number of jumps to reach end176
858Tree Traversal (Preorder, Inorder & Postorder)176
859Subset with sum divisible by m176
860Insert Delete GetRandom176
861Valid Parentheses Leetcode Solution176
862Check if a given array can represent Preorder Traversal of Binary Search Tree176
863Interval Tree175
864Partition List Leetcode Solution175
865Design a Stack With Increment Operation Leetcode Solution175
866Minimum Sum Path in a Triangle175
867An Interesting Method to generate Binary Numbers from 1 to n175
868Path with maximum average value175
869Union and Intersection of two Linked Lists175
870Remove Duplicates from Sorted List II175
871Remove Duplicates from Sorted List LeetCode Solution175
872Alien Dictionary LeetCode Solution175
873Iterative Preorder Traversal175
874Can Place Flowers LeetCode Solution175
875Brightest Position on Street LeetCode Solution174
876Count ways to reach the nth stair using step 1, 2 or 3174
877Infix to Postfix174
878Spiral Matrix II Leetcode Solution174
879Dividing Array into Pairs With Sum Divisible by K174
880Minimum swaps to make sequences increasing174
881Sequences of given length where every element is more than or equal to twice of previous174
882Convert BST to Min Heap174
883Get Maximum in Generated Array Leetcode Solution174
884Minesweeper LeetCode Solution174
885Sum of nearest smaller and greater number173
886Number of Distinct Islands Leetcode Solution173
887Water Bottles Leetcode Solution173
888Rearrange Array such that arr[i] >= arr[j] if i is even and arr[i] <= arr[j] if i is odd and j < i173
889Sort Colors173
890Least Number of Unique Integers after K Removals Leetcode Solution173
891Pattern Occurrences using Stack173
892Find all triplets with zero sum173
893Friends Pairing Problem173
894Find distance between two nodes of a Binary Tree173
895Find the Only Repetitive Element Between 1 to N-1173
896Level order Traversal in Spiral Form173
897Maximum Score After Splitting a String Leetcode Solution173
898Check whether a given Binary Tree is Complete or not173
899Maximum size subarray sum equals k173
900Find the subarray with least average173
901GCDs of given index ranges in an array173
902Diagonal Traverse LeetCode Solution173
903Guess Number Higher or Lower II173
904Sorted Array to Balanced BST173
905Range LCM Queries172
906Matrix Chain Multiplication172
907Range sum queries without updates172
908Check if any two intervals overlap among a given set of intervals172
909Delete And Earn172
910Insert into a Binary Search Tree Leetcode Solution172
911Best Time to Buy and Sell Stock with Transaction Fee Leetcode Solution172
912Shortest Word Distance Leetcode Solution172
913Lexicographical Numbers Leetcode Solution172
914Median of Two Sorted Arrays171
915Diagonal Traversal LeetCode Solution171
916Time Based Key-Value Store LeetCode Solution171
917Robot Bounded In Circle LeetCode Solution171
918Difference Array | Range update query in O(1)171
919Count Negative Numbers in a Sorted Matrix LeetCode Solution171
920A program to check if a binary tree is BST or not171
921All Unique Triplets that Sum up to a Given Value171
922Alien Dictionary171
923Averages of Levels in Binary Tree171
924Iterative Postorder Traversal Using Two Stacks171
925Destination City Leetcode Solution171
926Rearrange an Array Such that arr[i] is equal to i170
927Rearrange Spaces Between Words Leetcode Solution170
928Set Matrix Zeroes Leetcode Solution170
929Construct Complete Binary Tree from its Linked List Representation170
930Binary Tree Longest Consecutive Sequence LeetCode Solution170
931Check if the given array can represent Level Order Traversal of Binary Search Tree170
932Construct the Rectangle Leetcode Solution170
933My Calendar I LeetCode Solution170
934Three way partitioning of an array around a given range170
935Maximum Frequency Stack Leetcode Solution169
936Find Common Characters Leetcode Solution169
937Queue using Stacks169
938Product of Array Except Self LeetCode Solution169
939Count Subarrays with Same Even and Odd Elements169
940Vertical sum in a given binary tree169
941Trim a Binary Search Tree169
942Special Positions in a Binary Matrix Leetcode Solution169
943Count Submatrices With All Ones LeetCode Solution169
944Convert Sorted List to Binary Search Tree169
945Intersection of Two Linked Lists LeetCode Solution169
946Number of Equivalent Domino Pairs Leetcode Solution169
947Merge Two Sorted Lists Leetcode169
948K’th Largest Element in BST when modification to BST is not allowed169
949Spiral Matrix III LeetCode Solution169
950Palindrome Partitioning Leetcode Solution168
951Remove Duplicates from Sorted List II LeetCode Solution168
952Largest area rectangular sub-matrix with equal number of 1’s and 0’s168
953Analyze User Website Visit Pattern LeetCode Solution168
954Word Break168
955Three Consecutive Odds Leetcode Solution168
956Strongly Connected Component168
957Binary array after M range toggle operations168
958Minimum Height Trees LeetCode Solution168
959Longest Palindromic Subsequence167
9604Sum167
961Sign of the Product of an Array LeetCode Solution167
962Kth Smallest Element in a BST Leetcode Solution167
963Climbing stairs167
964Create Maximum Number167
9653 Sum167
966BFS for Disconnected Graph167
967Construct BST from its given Level Order Traversal167
968Queries for GCD of all numbers of an array except elements in a given range167
969Combination Sum IV LeetCode Solution166
970Count subarrays where second highest lie before highest166
971Merging Intervals166
972Count pair with Given Sum166
973Longest subsequence such that difference between adjacents is one166
974Maximum Product Subarray166
975Stone Game II Leetcode166
976Unique Paths II166
977Largest Number Leetcode Solution165
978Serialize and Deserialize Binary Tree165
979Count Primes in Ranges165
980Design Hit Counter LeetCode Solution165
981Number of palindromic paths in a matrix165
982Maximize Sum of Array after K Negations Leetcode Solution165
983Breadth First Search (BFS) for a Graph165
984Reverse Nodes in K-Group165
985Find Maximum of Minimum for Every Window Size in a Given Array165
986Depth First Search (DFS) for a Graph165
987Symmetric Tree165
988Longest Nice Substring LeetCode Solution164
989Maximum Length of Repeated Subarray164
990Valid Boomerang Leetcode Solution164
991Binary Search Tree Delete Operation164
992Find number of pairs in an array such that their XOR is 0164
993Maximum Product of Indexes of Next Greater on Left and Right164
994Asteroid Collision LeetCode Solution164
995Find the First Circular Tour that visits all the Petrol Pumps164
996The Maze III LeetCode Solution164
997Can Make Arithmetic Progression From Sequence Leetcode Solution164
998K Closest Points to Origin Leetcode Solution163
999Count pairs from two sorted arrays whose sum is equal to a given value x163
1000Next Permutation Leetcode Solution163
1001String Matching in an Array Leetcode Solution163
1002Palindrome Partitioning163
1003Print Fibonacci sequence using 2 variables163
1004Maximum Subarray Sum Excluding Certain Elements163
1005Kth Smallest Element in a Sorted Matrix LeetCode Solution163
1006Consecutive Characters LeetCode Solution163
1007Graph Valid Tree LeetCode Solution163
1008The Painter’s Partition Problem162
1009Length of Longest Fibonacci Subsequence162
1010Minimum Index Sum of Two Lists162
1011Level Order Traversal of Binary Tree162
1012Maximum Sum of 3 Non-Overlapping Subarrays162
1013Collect maximum points in a grid using two traversals162
1014Find postorder traversal of BST from preorder traversal162
1015Decrypt String from Alphabet to Integer Mapping Leetcode Solution162
1016Find the Difference Leetcode Solution162
1017Shortest Completing Word Leetcode Solution162
1018Shuffle 2n integers as a1-b1-a2-b2-a3-b3-..bn without using extra space162
1019Balanced Binary Tree162
1020Scramble String LeetCode Solution162
1021Height of a generic tree from parent array162
1022Validate Binary Search Tree162
1023Maximum Number of Ways to Partition an Array LeetCode Solution161
1024Largest divisible pairs subset161
1025Maximum length subsequence with difference between adjacent elements as either 0 or 1161
1026Generate Parentheses Leetcode Solution161
1027Merge Sort161
1028Segment Tree161
1029Find Duplicate Subtrees161
1030Print Next Greater Number of Q queries161
1031Available Captures for Rook Leetcode Solution161
1032Invalid Transactions LeetCode Solution161
1033Newman-Conway Sequence161
1034Maximum difference between frequency of two elements such that element having greater frequency is also greater161
1035K maximum sums of overlapping contiguous sub-arrays161
1036Advantages of BST over Hash Table160
1037Number Of Longest Increasing Subsequence160
1038Rearrange an array such that ‘arr[j]’ becomes ‘i’ if ‘arr[i]’ is ‘j’160
1039Binary Search Tree160
1040Insertion in a Binary Tree160
1041Construction of Longest Increasing Subsequence (N log N)160
1042Make The String Great Leetcode Solution160
1043Next Greater Element III LeetCode Solution160
1044Construct Binary Tree from given Parent Array representation160
1045Largest Substring Between Two Equal Characters Leetcode Solution160
1046Custom Sort String Leetcode Solution160
1047First missing positive160
1048Find a Peak Element II LeetCode Solution159
1049Friends Of Appropriate Ages LeetCode Solution159
1050Rearrange array such that even positioned are greater than odd159
1051Count minimum steps to get the given desired array159
1052Boundary Traversal of binary tree159
1053Compute nCr % p159
1054Boolean Parenthesization Problem159
1055Check If a Word Occurs As a Prefix of Any Word in a Sentence Leetcode Solution159
1056Move all negative elements to end in order with extra space allowed159
1057Bitwise AND of Numbers Range LeetCode Solution158
1058Rearrange array such that even index elements are smaller and odd index elements are greater158
1059Path Sum II LeetCode Solution158
1060Iterative Depth First Traversal of Graph158
1061Kill Process LeetCode Solution158
1062Build an Array With Stack Operations Leetcode Solution158
1063Double the first element and move zero to end158
1064Maximum subsequence sum such that no three are consecutive158
1065Subarrays with K Different Integers Leetcode Solution158
1066Remove Duplicates from Sorted Array II Leetcode Solution157
1067Morris Inorder Traversal157
1068Recover Binary Search Tree Leetcode Solution157
1069Remove Palindromic Subsequences Leetcode Solution157
1070Defanging an IP Address LeetCode Solution157
1071Level order traversal using two Queues157
1072Determine Whether Matrix Can Be Obtained By Rotation LeetCode Solution157
1073Find Peak Element157
1074Largest BST Subtree LeetCode Solution157
1075Regular Expression Matching Regular Expression Matching LeetCode Solution156
1076Partition Equal Subset Sum156
1077Maximum weight transformation of a given string156
1078Minimum Size Subarray Sum156
1079Add two numbers156
1080Smallest Common Region Leetcode Solution156
1081Lowest Common Ancestor156
1082Print Right View of a Binary Tree156
1083Employee Importance LeetCode Solution156
1084Palindrome Permutation LeetCode Solution156
1085Binary Tree Right Side View LeetCode Solution155
1086Longest Bitonic Subsequence155
1087Increasing Triplet Subsequence LeetCode Solution155
1088Number of Closed Islands Leetcode Solution155
1089Ugly Number II LeetCode Solution155
1090Remove duplicates from sorted array155
1091Ugly Numbers155
1092Maximize Distance to Closest Person LeetCode Solution155
1093Implement Trie (Prefix Tree) Leetcode Solution155
1094Super Ugly Number155
1095Bus Routes Leetcode Solution154
1096Populating Next Right Pointers in Each Node Leetcode Solution154
1097Construct Binary Tree from Preorder and Postorder Traversal LeetCode Solution154
1098Find maximum difference between nearest left and right smaller elements154
1099Valid Tic-Tac-Toe State LeetCode Solution154
1100Palindromic Substrings Leetcode Solution154
1101Path Sum154
1102Sum of Even Numbers After Queries154
1103Binary Tree Data Structure153
1104Search in Sorted Rotated Array153
1105Thousand Separator Leetcode Solution153
1106Find Three Element From Different Three Arrays Such That a + b + c = sum153
1107Find whether a subarray is in form of a mountain or not153
1108Divisible Pairs Counting153
1109Moser-de Bruijn Sequence153
1110Reformat The String Leetcode Solution153
1111Number of siblings of a given Node in n-ary Tree153
1112Print all triplets in sorted array that form AP153
1113Find the minimum distance between two numbers153
1114Number of Students Doing Homework at a Given Time Leetcode Solution152
1115Count Largest Group Leetcode Solution152
1116Find Smallest Range Containing Elements from k Lists152
1117Mean of Array After Removing Some Elements Leetcode Solution152
1118Day of the Year Leetcode Solution152
1119Cells with Odd Values in a Matrix LeetCode Solution152
1120Kth Smallest Product of Two Sorted Arrays LeetCode Solution152
1121Search Insert Position151
1122Products of ranges in an array151
1123Level of Each node in a Tree from source node151
1124Distinct Subsequences151
1125Iterative method to find ancestors of a given binary tree151
1126Root to Leaf path with target sum Leetcode Solutions151
1127Clone a Binary Tree with Random Pointers151
1128Serialize and Deserialize Binary Tree LeetCode Solution151
1129Compare Strings by Frequency of the Smallest Character Leetcode Solution150
1130Third Maximum Number Leetcode Solution150
1131Minimum Absolute Difference in BST Leetcode Solution150
1132Longest Increasing Consecutive Subsequence150
1133Prime Palindrome LeetCode Solution150
1134Topological Sorting150
1135Constant time range add operation on an array150
1136Find Two Non-overlapping Sub-arrays Each With Target Sum LeetCode Solution150
1137Maximum Depth Of Binary Tree149
1138Queries for Number of Distinct Elements in a Subarray149
1139Longest Repeated Subsequence149
1140Find maximum length Snake sequence149
1141Bottom View of a Binary Tree149
1142Maximum Product Subarray149
1143Convert BST into a Min-Heap without using array149
1144Construct K Palindrome Strings LeetCode Solution149
1145Minimum sum of squares of character counts in a given string after removing k characters148
1146Print modified array after executing the commands of addition and subtraction148
1147Rotate Array148
1148Web Crawler LeetCode Solution148
1149Longest Subarray of 1’s After Deleting One Element LeetCode Solution148
1150Diameter of N-Ary Tree LeetCode Solution148
1151Subset Sum Problem in O(sum) space147
1152Write Code to Determine if Two Trees are Identical147
1153Find a sorted subsequence of size 3 in linear time147
1154Search an Element in Sorted Rotated Array147
1155Delete Nodes and Return Forest Leetcode Solution147
1156Count even length binary sequences with same sum of first and second half bits147
1157Maximum Product of Splitted Binary Tree LeetCode Solution147
1158Cutting a Rod147
1159Closest Binary Search Tree Value Leetcode Solution147
1160Minimum Score Triangulation of Polygon Leetcode Solution147
1161Priority Queue147
1162Minimum Cost to Move Chips to The Same Position LeetCode Solution146
1163Find Largest Value in Each Tree Row LeetCode Solution146
1164Search Suggestions System LeetCode Solution146
1165Golomb sequence146
1166Maximize sum of consecutive differences in a circular array146
1167Reformat Date LeetCode Solution146
1168Matchsticks to Square Leetcode Solution146
1169Swap Nodes In Pairs146
1170K’th Largest element in BST using constant extra space145
1171Possible Bipartition LeetCode Solution145
1172Closest Leaf in a Binary Tree LeetCode Solution145
1173Given a binary tree, how do you remove all the half nodes?145
1174Decision Tree145
1175Count Pairs Whose Products Exist in Array145
1176Minimum Sideway Jumps LeetCode Solution145
1177Minimum Swaps To Make Sequences Increasing LeetCode Solution145
1178Transform a BST to Greater sum Tree145
1179Minimum Moves to Equal Array Elements LeetCode Solution145
1180Kth Smallest Number in Multiplication Table Leetcode Solution145
1181Contiguous Array LeetCode Solution145
1182Red-Black Tree Introduction145
1183Path Crossing Leetcode Solution144
1184Remove Max Number of Edges to Keep Graph Fully Traversable Leetcode Solution144
1185Binary Tree to Binary Search Tree Conversion144
1186Maximum Value at a Given Index in a Bounded Array LeetCode Solution144
1187Decrease Elements To Make Array Zigzag LeetCode Solution144
1188Reverse a Path in BST using Queue144
1189Check Array Formation Through Concatenation Leetcode Solution144
1190First Bad Version144
1191Merge two BSTs with limited extra space144
1192Find the smallest binary digit multiple of given number144
1193Maximum Binary Tree143
1194Valid Triangle Number143
1195Maximum number of segments of lengths a, b and c143
1196Replace two consecutive equal values with one greater143
1197Perfect Squares LeetCode Solution143
1198Convert Integer to the Sum of Two No-Zero Integers Leetcode Solution143
1199Sum of Left Leaves LeetCode Solution143
1200Divide Two Integers Leetcode Solution142
1201Sliding Window Median Leetcode Solution142
1202Concatenation of Array LeetCode Solution142
1203Factorial Trailing Zeroes LeetCode Solution142
1204Print n terms of Newman-Conway Sequence142
1205Queue Reconstruction by Height142
1206Number of Orders in the Backlog Leetcode Solution142
1207Maximum sum of pairs with specific difference142
1208Convert Sorted Array to Binary Search Tree LeetCode Solutions142
1209Swapping Nodes in a Linked List Leetcode Solution141
1210Valid Perfect Square LeetCode Solution141
1211Maximum sum bitonic subarray141
1212Champagne Tower LeetCode Solution140
1213Kth Smallest Element in a BST140
1214Lowest Common Ancestor of a Binary Tree Leetcode Solution140
1215New 21 Game140
1216Maximum sum of a path in a Right Number Triangle140
1217Lowest Common Ancestor in Binary Search Tree140
1218How to print maximum number of A’s using given four keys140
1219Longest Common Prefix Using Word by Word Matching139
1220Merge k Sorted Lists Leetcode Solution139
1221Find minimum number of merge operations to make an array palindrome139
1222Flatten 2D Vector LeetCode Solution139
1223Array Queries for multiply replacements and product139
1224Integer Break LeetCode Solution139
1225Queries on Probability of Even or Odd Number in given Ranges139
1226Guess The Word139
1227Filter Restaurants by Vegan-Friendly, Price and Distance Leetcode Solution138
1228Range Sum Query using Sparse Table138
1229Check if all levels of two Binary Tree are anagrams or not138
1230Graph and its representation138
1231Mean of range in array138
1232Moving Stones Until Consecutive Leetcode Solution138
1233Maximum Array from Two given Arrays Keeping Order Same137
1234Missing Number137
1235BST to a Tree with Sum of all Smaller Keys137
1236Contiguous Array137
1237Design Skiplist LeetCode Solution137
1238Range Queries for Longest Correct Bracket Subsequence137
1239Maximize Elements Using Another Array137
1240Print modified array after multiple array range increment operations137
1241Find Minimum in Rotated Sorted Array II LeetCode Solution137
1242LRU Cache Leetcode Solution137
1243Maximum Sum Increasing Subsequence137
1244Count Subsets Having Distinct Even Numbers136
1245Maximum Product Subarray136
1246Bold Words in String LeetCode Solution136
1247Min Cost Climbing Stairs LeetCode Solution136
1248Write a function to get the intersection point of two Linked Lists136
1249Largest Plus Sign Leetcode Solution136
1250Minimum Remove to Make Valid Parentheses LeetCode Solution135
1251The kth Factor of n Leetcode Solution135
1252Check in binary array the number represented by a subarray is odd or even135
1253Arithmetic Slices II – Subsequence LeetCode Solution134
1254Check if each internal node of a BST has exactly one child134
1255Different Ways to Add Parentheses Leetcode Solution134
1256Graph Cloning134
1257Parallel Courses II LeetCode Solution134
1258Find k-th smallest element in BST (Order Statistics in BST)134
1259Power of Two134
1260Minimum Time to Collect All Apples in a Tree LeetCode Solution133
1261Check if two nodes are on the same path in a Tree133
1262Smallest Range II Leetcode Solution132
1263Check for Identical BSTs without building the trees132
1264Image Overlap LeetCode Solution132
1265Print Ancestors of a Given Binary Tree Node Without Recursion132
1266Symmetric Tree LeetCode Solution Leetcode Solution132
1267Check Completeness of a Binary Tree LeetCode Solution132
1268Verify Preorder Serialization of a Binary Tree131
1269Longest Substring Without Repeating Characters Leetcode Solution130
1270Excel Sheet Column Title LeetCode Solution130
1271Orderly Queue LeetCode Solution130
1272Koko Eating Bananas LeetCode Solution130
1273Arranging Coins Leetcode Solution129
1274Merge Sorted Array129
1275Next greater element129
1276Vertical Order Traversal of Binary Tree LeetCode Solution128
1277Number of elements less than or equal to a given number in a given subarray128
1278Largest Submatrix With Rearrangements LeetCode Solution128
1279Count and Toggle Queries on a Binary Array128
1280Array Nesting Leetcode Solution127
1281Palindrome Partitioning126
1282Check If a String Can Break Another String Leetcode Solution126
1283Add Two Numbers II Leetcode Solution125
1284Peeking Iterator LeetCode Solution125
1285Newman–Shanks–Williams prime125
1286Palindrome Number LeetCode Solution125
1287Insert Delete GetRandom O(1) Leetcode Solution125
1288Queries for Decimal Values of Subarrays of a Binary Array125
1289Maximum product of an increasing subsequence125
1290Check if X can give change to every person in the Queue125
1291Range Minimum Query (Square Root Decomposition and Sparse Table)124
1292Find maximum average subarray of k length124
1293Find the Winner of the Circular Game LeetCode Solution124
1294Encoded String With Shortest Length LeetCode Solution122
1295Number of Subsequences That Satisfy the Given Sum Condition LeetCode solution122
1296Continuous Subarray Sum LeetCode Solution121
1297Check given array of size n can represent BST of n levels or not121
1298Binary Tree to Binary Search Tree Conversion using STL set120
1299Jump Game IV LeetCode Solution119
1300Reach a Number LeetCode Solution119
1301Minimum Possible Integer After at Most K Adjacent Swaps On Digits LeetCode Solution119
1302Number of indexes with equal elements in given range119
1303Random Pick Index LeetCode Solution119
1304Minimum Number of People to Teach LeetCode Solution118
1305Minimum Total Space Wasted With K Resizing Operations LeetCode Solution117
1306Convert a BST to a Binary Tree such that sum of all greater keys is added to every key117
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
1318Monotonic Array Leetcode Solution105
1319Odd Even Linked List Leetcode Solution104
1320Substring with Concatenation of All Words Leetcode Solution104
1321Longest Common Subsequence LeetCode Solution102
1322Binary Tree Inorder Traversal LeetCode Solution101
1323Decode String Leetcode Solution101
1324Find the Town Judge LeetCode Solution100
1325Maximum Population Year LeetCode Solution100
1326Shortest Unsorted Continuous Subarray LeetCode Solution95
1327Rectangle Overlap LeetCode Solution94
1328Best Meeting Point LeetCode Solution94
1329Maximum Population Year LeetCode Solution93
1330Find the Town Judge LeetCode Solution92
1331Sum Root to Leaf Numbers LeetCode Solution91
1332Insert into a Sorted Circular Linked List LeetCode Solution91
1333Flatten Binary Tree to Linked List LeetCode Solution89
1334Design Add and Search Words Data Structure LeetCode Solution89
1335Stone Game IV LeetCode Solution88
1336Is Graph Bipartite? LeetCode Solution87
1337Range Sum Query 2D – Immutable LeetCode Solution87
1338Reveal Cards In Increasing Order Leetcode Solution86
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 Solution68
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 Solution45
1352Camelcase Matching Leetcode Solution45
1353Valid Anagram Leetcode Solution44
1354Most Stones Removed with Same Row or Column LeetCode Solution43
1355Container With Most Water LeetCode Solution42
1356Group Anagrams LeetCode Solution42
1357Sliding Window Maximum LeetCode Solution42
1358Next Permutation LeetCode Solution41
1359High Five LeetCode Solution41
1360Binary Search LeetCode Solution40
1361Find Peak Element LeetCode Solution40
1362Pairs of Songs With Total Durations Divisible by 60 LeetCode Solution38
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
1368Flatten Binary Tree to Linked List LeetCode Solution35
1369Group Shifted Strings Leetcode Solution34
1370Sentence Screen Fitting LeetCode Solution33
1371Count Good Nodes in Binary Tree LeetCode Solution32
1372The Number of Weak Characters in the Game LeetCode Solution32
1373Isomorphic Strings LeetCode Solution32
1374Swim in Rising Water LeetCode Solution32
1375Closest Binary Search Tree Value II LeetCode Solution31
1376Peak Index in a Mountain Array LeetCode Solution31
1377Insert Delete GetRandom O(1) – Duplicates allowed LeetCode Solution31
1378All Possible Full Binary Trees LeetCode Solution27
1379Split Linked List in Parts Leetcode Solution27
1380Validate Stack Sequences LeetCode Solution26
1381Single Element in a Sorted Array LeetCode Solution26
1382Lowest Common Ancestor of a Binary Search Tree Leetcode Solution25
1383Max Sum of Two Non-Overlapping Subarrays LeetCode Solution25
1384Best Time to Buy and Sell Stock IV LeetCode Solution24
1385Minimum Increment to Make Array Unique Leetcode Solution24
1386Greatest Sum Divisible by Three LeetCode Solution24
1387Find First and Last Position of Element in Sorted Array LeetCode Solution24
1388Implement strStr() LeetCode Solution23
1389Break a Palindrome LeetCode Solution22
1390Implement Rand10() Using Rand7() Leetcode Solution22
1391Stone Game IV LeetCode Solution22
1392Trapping Rain Water II LeetCode Solution22
1393Contains Duplicate LeetCode Solution20
1394Detect Squares LeetCode Solution20
1395Fibonacci Number LeetCode Solution19
1396Remove All Ones With Row and Column Flips Leetcode Solution19
1397Design Bounded Blocking Queue LeetCode Solution18
1398Reverse Nodes in k-Group LeetCode Solution17
1399Invert Binary Tree LeetCode Solution17
1400Minimum Number of Operations to Move All Balls to Each Box LeetCode Solution16
1401Total Hamming Distance LeetCode Solution14
1402Candy LeetCode Solution13
1403Unique Paths III LeetCode Solution11
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