LeetCode

Work through a sheet in order: problems within each section build on one another. Every solution explains the intuition, the algorithm and its complexity before showing the code.

Company interview lists6Striver SDE Sheet177Striver DP Sheet5Blind 7511More problems12

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Striver SDE SheetArrays

• Pascal's Triangle$O(n^2)$
• Next Permutation$O(n)$
• Set Matrix Zeroes$O(n \cdot m \cdot (n + m))$
• Best Time to Buy and Sell Stock$O(n)$
• Maximum Subarray$O(n)$
• Sort Colors$O(n)$

Striver SDE SheetArrays Part-II

• Merge Intervals$O(n \log n)$
• Merge Sorted Array$O(m + n)$
• Repeat and Missing Number Array$O(n)$
• Rotate Image$O(n^2)$
• Count Inversions$O(n \log n)$
• Find the Duplicate Number$O(n)$

Striver SDE SheetArrays Part-III

• Reverse Pairs$O(n \log n)$
• Search a 2D Matrix$O(\log n + \log m)$
• Pow(x, n)$O(\log n)$
• Majority Element II$O(n)$
• Unique Paths$O(\min(m, n))$
• Majority Element$O(n \log n)$

Striver SDE SheetArrays Part-IV

• 4Sum$O(n^3 \log n)$
• Longest Consecutive Sequence$O(n \log n)$
• Subarray with given XOR$O(n)$
• Longest Subarray Zero Sum$O(n)$
• Two Sum$O(n)$
• Longest Substring Without Repeating Characters$O(n)$

Striver SDE SheetLinked List

• Add Two Numbers$O(\max(m, n))$
• Delete Node in a Linked List$O(1)$
• Reverse Linked List$O(n)$
• Middle of the Linked List$O(n)$
• Merge Two Sorted Lists$O(n + m)$
• Remove Nth Node From End of List$O(L)$

Striver SDE SheetLinked List Part-II

• Palindrome Linked List$O(n)$
• Flattening a Linked List$O(N \cdot k)$
• Linked List Cycle$O(n \log n)$
• Reverse Nodes in k-Group$O(n)$
• Intersection of Two Linked Lists$O((n + m) \log n)$
• Linked List Cycle II$O(n \log n)$

Striver SDE SheetLinked List and Arrays

• Trapping Rain Water$O(n)$
• Max Consecutive Ones$O(n)$
• Remove Duplicates from Sorted Array$O(n)$
• 3Sum$O(n^2 \log n)$
• Copy List with Random Pointer$O(n \log n)$
• Rotate List$O(n)$

Striver SDE SheetGreedy Algorithm

• Minimum Platforms$O(n \log n)$
• Job Sequencing Problem$O(n \log n + n \cdot D)$
• Number of Coins$O(M \cdot V)$
• Maximum Meetings$O(n \log n)$
• Fractional Knapsack$O(n \log n)$

Striver SDE SheetRecursion

• Combination Sum II$O(2^n \cdot n)$
• Subset Sums$O(N \cdot 2^N)$
• Permutation Sequence$O(n^2)$
• Combination Sum$O\left(\prod_i (T / c_i + 1)\right)$
• Subsets II$O(n^2 \cdot 2^n)$
• Palindrome Partitioning$O(n^2 \cdot 2^n)$

Striver SDE SheetRecursion and Backtracking

• Sudoku Solver$O(9^m)$
• Word Break$O(n^3)$
• Rat in a Maze Problem I$O(3^{n^2})$
• N-Queens$O(n \cdot n!)$
• M-Coloring Problem$O(n \cdot m^n)$
• Permutations$O(n \cdot n!)$

Striver SDE SheetBinary Search

• Allocate Books$O(n \log S)$
• K-th element of two sorted Arrays$O(k)$
• Median of Two Sorted Arrays$O(\log(\min(N1, N2)))$
• The N-th root of an integer$O(1)$
• Single Element in a Sorted Array$O(n + \log R \cdot \log n)$
• Matrix Median$O(n \log m \cdot \log R)$
• Search in Rotated Sorted Array$O(\log n)$
• Chess Tournament$O(n \log n + n \log R)$

Striver SDE SheetHeaps

• Merge K Sorted Arrays$O(N \log N)$
• Kth Largest Element in an Array$O(n)$
• Top K Frequent Elements$O(n \log n)$
• Maximum Sum Combinations$O(n \log n + C \log C)$
• Find Median from Data Stream$O(\log n)$

Striver SDE SheetStack and Queue

• Implement a Queue using array$O(1)$
• Next Greater Element I$O(n \cdot m)$
• Implement Stack using Queues$O(1)$
• Implement Stack Using Arrays$O(1)$
• Implement Queue using Stacks$O(1)$
• Sort a Stack$O(n^2)$
• Valid Parentheses$O(n)$

Striver SDE SheetStack and Queue Part-II

• Sliding Window Maximum$O(n \log k)$
• Nearest Smaller Element$O(n)$
• Rotting Oranges$O(k \cdot 3^{n \cdot m})$
• LFU Cache$O(\log n)$
• Online Stock Span$O(1)$
• Min Stack$O(1)$
• LRU Cache$O(1)$
• Largest Rectangle in Histogram$O(n)$
• The Celebrity Problem$O(n)$

Striver SDE SheetString

• Reverse Words in a String$O(n)$
• Repeated String Match$O((m / n + 1) \cdot (m + n) \cdot m)$
• String to Integer (atoi)$O(n)$
• Roman to Integer$O(n)$
• Longest Palindromic Substring$O(n^3)$
• Longest Common Prefix$O(n \cdot m)$

Striver SDE SheetString-II

• Valid Anagram$O(n)$
• Minimum Characters required to make a String Palindromic$O(n \log n)$
• Implement strStr()$O((n + m) \log M)$
• Compare Version Numbers$O(n + m)$
• Count and Say$O(n \cdot L)$

Striver SDE SheetBinary Tree

• Binary Tree Preorder Traversal$O(n)$
• Left View of Binary Tree$O(n \log h)$
• Tree Traversals$O(n)$
• Maximum Width of Binary Tree$O(n)$
• Binary Tree Postorder Traversal$O(n)$
• Binary Tree Preorder Traversal$O(n)$
• Path to Given Node$O(n)$
• Vertical Order Traversal of a Binary Tree$O(n \log n)$
• Binary Tree Inorder Traversal$O(n)$
• Top View of Binary Tree$O(n \log n)$
• Bottom View of Binary Tree$O(n \log n)$
• Binary Tree Inorder Traversal$O(n)$

Striver SDE SheetBinary Tree Part-II

• Binary Tree Zigzag Level Order Traversal$O(n)$
• Binary Tree Level Order Traversal$O(n \log h)$
• Boundary Traversal of binary tree$O(n)$
• Lowest Common Ancestor of a Binary Tree$O(n)$
• Same Tree$O(n)$
• Maximum Depth of Binary Tree$O(n)$
• Balanced Binary Tree$O(n \log n)$
• Diameter of Binary Tree$O(n \log n)$

Striver SDE SheetBinary Tree part-III

• Construct Binary Tree from Preorder and Inorder Traversal$O(n^2)$
• Construct Binary Tree from Inorder and Postorder Traversal$O(n^2)$
• Symmetric Tree$O(n)$
• Flatten Binary Tree to Linked List$O(n)$
• Children Sum Property$O(n)$
• Binary Tree Maximum Path Sum$O(n \log n)$
• Mirror Tree$O(n)$

Striver SDE SheetBinary Search Tree

• Lowest Common Ancestor of a Binary Search Tree$O(n)$
• Search in a Binary Search Tree$O(h)$
• Construct Binary Search Tree from Preorder Traversal$O(n^2)$
• Validate Binary Search Tree$O(n)$
• Convert Sorted Array to Binary Search Tree$O(n^2)$
• Populating Next Right Pointers in Each Node$O(n \log h)$

Striver SDE SheetBinary Search Tree Part-II

• Two Sum IV - Input is a BST$O(n \log n)$
• Kth largest element in BST$O(n)$
• Maximum Sum BST in Binary Tree$O(n)$
• Binary Search Tree Iterator$O(1)$
• Ceil from BST$O(h)$
• Kth Smallest Element in a BST$O(n)$
• Serialize and Deserialize Binary Tree$O(n)$
• Floor in BST$O(h)$

Striver SDE SheetBinary Trees[Miscellaneous]

• Kth Largest Element in an Array$O(n)$
• Flood Fill$O(n \cdot m)$
• Distinct Numbers in Window$O(n \log B)$
• Flatten Binary Tree to Linked List$O(n)$
• Kth Largest Element in a Stream$O(n)$
• Find Median from Data Stream$O(\log n)$

Striver SDE SheetGraph

• Is Graph Bipartite?$O(V \cdot (V + E))$
• Number of Islands$O(n \cdot m)$
• Course Schedule$O(V + E)$
• Clone Graph$O((V + E) \log V)$
• DFS of Graph$O(V + E)$
• Topological sort$O(V + E)$
• BFS of graph$O(V + E)$

Striver SDE SheetGraph Part-II

• Maximum Number of Non-Overlapping Substrings$O(26 \cdot n)$
• Dijkstra Algorithm$O((V + E) \log V)$
• Floyd Warshall Algorithm$O(V^3)$
• Bellman-Ford Algorithm$O(V \cdot E)$
• Minimum Spanning Tree

Striver SDE SheetDynamic Programming

• Longest Increasing Subsequence$O(n \log n)$
• Longest Common Subsequence$O(n \cdot m)$
• Ones and Zeroes$O(l \cdot m \cdot n + L)$
• Matrix Chain Multiplication$O(n^3)$
• Edit Distance$O(n \cdot m)$
• Maximum sum increasing subsequence$O(n^2)$
• Maximum Product Subarray$O(n)$

Striver SDE SheetDynamic Programming Part-II

• Word Break$O(n^3)$
• Partition Equal Subset Sum$O(n \cdot sm)$
• Maximum Profit in Job Scheduling$O(n \log n)$
• Minimum Path Sum$O(n \cdot m)$
• Coin Change$O(A \cdot k)$
• Palindrome Partitioning$O(n^2 \cdot 2^n)$
• Minimum Cost to Cut a Stick$O(m^3)$
• Super Egg Drop$O(k \log n)$

Striver SDE SheetTrie

• Subsets$O(n^2 \cdot 2^n)$
• Maximum XOR of Two Numbers in an Array$O(n \log M)$
• Implement Trie (Prefix Tree)$O(L)$
• Maximum XOR With an Element From Array$O(n \log n + q \log q + 31(n + q))$

Striver DP Sheet1D DP

• Climbing Stairs$O(n)$
• Frog with k jumps$O(n \cdot k)$
• Maximum sum of non-adjacent elements$O(n)$
• House Robber$O(n)$
• House Robber II$O(n)$

Blind 75Arrays

• Two Sum$O(n)$
• Best Time to Buy and Sell Stock$O(n)$
• Contains Duplicate$O(n \log n)$
• Product of Array Except Self$O(n)$
• Maximum Subarray$O(n)$
• Maximum Product Subarray$O(n)$
• Find Minimum in Rotated Sorted Array$O(\log n)$
• Find Minimum in Rotated Sorted Array II$O(\log n)$
• Search in Rotated Sorted Array$O(\log n)$
• 3Sum$O(n^2 \log n)$
• Container With Most Water$O(n)$

More problems

• Add Binary$O(n^2)$
• Course Schedule II$O(V + E)$
• Group Anagrams$O(n \cdot L \log L + n \cdot L \log n)$
• K Closest Points to Origin$O(n \log n)$
• Merge k Sorted Lists$O(kN)$
• Most Common Word$O(n + b)$
• Multiply Strings$O(n \cdot m)$
• Top K Frequent Words$O(n + m \log k)$
• Valid Number$O(n)$
• Word Break II$O(2^n \cdot D \cdot L)$
• Word Search$O(n \cdot m \cdot 3^L \cdot L)$
• Word Search II$O(W \cdot n \cdot m \cdot 3^L \cdot L)$