LeetCode 🔶

LeetCode training exercises webpage for reviewing

Solutions are provided for each question including different languages and different ideas

Challenge Ongoing (300/350)

• 100 Problems Solved ⭕️
• 200 Problems Solved ⭕️
• 250 Problems Solved ⭕️
• 300 Problems Solved ️️⭕️
• 350 Problems Solved ❌
• 400 Problems Solved ❌

Weekly Contest ✏️

Every Sunday 11:30am ~ 1:00pm (1.5hours)

Topics of Algorithm

• BFS
  • Binary Tree Level Order Traversal (easy)
  • Reverse Level Order Traversal (easy)
  • Zigzag Traversal (medium)
  • Level Averages in a Binary Tree (easy)
  • Minimum Depth of a Binary Tree (easy)
  • Binary Tree Pruning
  • Leaf-Similar Trees
  • Maximum Depth of N-ary Tree
• DFS
  • Binary Tree Path Sum (easy)
  • All Paths for a Sum (medium)
  • Sum of Path Numbers (medium)
  • Path With Given Sequence (medium)
  • Count Paths for a Sum (medium)
  • employees Importance
  • Keys and Rooms
  • Max Area of Island
  • NumbersofIslands
  • RightSideView
  • Surrounding Blocks
  • Longest Increasing Path in a Matrix
  • Maximum Difference Between Node and Ancestor
• Back Tracing
  • Subsets With Duplicates (easy)
  • String Permutations by changing case (medium)
  • Balanced Parentheses (hard)
  • Unique Generalized Abbreviations (hard)
  • Combinations
  • Combination Sum
  • Combination Sum III
  • Generate Parentheses
  • Letter Case Permutation
  • Letter Combinations of a Phone Number
  • N-Queens
  • Subset (easy)
  • SubsetII
  • Permutations (medium)
  • Permutations II
  • Permutation Sequence
  • Numbers With Same Consecutive Differences
• Union Find
  • Friend Circles
  • Redundant Connection
• Binary Search
  • Order-agnostic Binary Search (easy)
  • Ceiling of a Number (medium)
  • Next Letter (medium)
  • Number Range (medium)
  • Search in a Sorted Infinite Array (medium)
  • Minimum Difference Element (medium)
  • Bitonic Array Maximum (easy)
  • Search in Rotated Sorted Array
  • Search in Rotated Sorted Array II
  • Search a 2D Matrix II
  • Pow(x, n)
• Greedy Algorithm
  • Jump Game II
  • Jump Game
  • Non-overlapping intervals
  • Is Subsequence
  • Maximum Swap
  • Partition Labels
  • Increasing Triplet Subsequence
  • Task Scheduler
  • Delete Columns to Make Sorted
  • Maximum Length of Pair Chain
  • Bag of Tokens
• Dynamic Programming
  • 0/1 Knapsack (medium)
  • Equal Subset Sum Partition (medium)
  • Subset Sum (medium)
  • Minimum Subset Sum Difference (hard)
  • Fib
  • House Robber II
  • Longest Consecutive Sequence
  • Longest Increasing SubString
  • Longest Palindromic Substrings
  • Maximum Product Subarray
  • Maximum Sum Subarray
  • Maximal Square
  • Minimum Path Sum
  • Minimum Falling Path Sum
  • Minimum ASCII Delete Sum for Two Strings
  • Tiangle minimum sum
  • UglyNumber
  • Unique Paths
  • UniquePathII
  • Unique Binary Search Trees
  • Unique Binary Search Trees II
  • Wiggle Subsequence
  • Interleaving String
  • Best Time to Buy and Sell Stock III
  • Best Time to Buy and Sell Stock with Cooldown
  • Best Time to Buy and Sell Stock with Transaction Fee
  • Coin Change
  • Palindromic Substrings
  • Edit Distance
  • Delete Operation for Two Strings
• Sliding Windows
  • Maximum Sum Subarray of Size K (easy)
  • Smallest Subarray with a given sum (easy)
  • Longest Substring with K Distinct Characters (medium)
  • Fruits into Baskets (medium)
  • No-repeat Substring (hard)
  • Longest Substring with Same Letters after Replacement (hard)
  • Longest Subarray with Ones after Replacement (hard)
  • Repeated DNA sequences
  • Permutation in String
• Hash Table
  • 4Sum II
  • Longest Nonrepeated substring
  • Bitwise ORs of substring
  • Implement Magic Dictionary
  • Top K Frequent Elements
  • 3 Sum
  • Arithmetic Slices
  • Group Anagrams
  • Long Pressed Name
  • Reorder Log Files
• Two Pointers
  • Pair with Target Sum (easy)
  • Remove Duplicates (easy)
  • Squaring a Sorted Array (easy)
  • Triplet Sum to Zero (medium)
  • Triplet Sum Close to Target (medium)
  • Triplets with Smaller Sum (medium)
  • Subarrays with Product Less than a Target (medium)
  • Dutch National Flag Problem (medium)
  • Minimum Size Subarray Sum
  • Minimum Window Substring
  • 3Sum Closest
  • 4Sum
  • Container With Most Water
  • Next Permutation
  • Trapping Rain Water
• Tree
  • Increasing order search tree
  • Kth Smallest Element in a BST
  • Validate Binary Search Tree
  • Smallest Subtree with all the Deepest Nodes
  • Binary Tree Pruning
  • Range Sum of BST
  • Diameter of Binary Tree
  • Subtree of Another Tree
  • Path Sum III
• Linked List
  • Reverse a LinkedList (easy)
  • Reverse a Sub-list (medium)
  • Reverse every K-element Sub-list (medium)
  • Find Kth to Tail (ListNode)
  • Linked List Components
  • Add Two Numbers
  • Delete Node in a Linked List
  • Odd Even Linked List
  • Merge k Sorted Lists
  • Remove Nth Node From End of List
  • Insertion Sort List
  • Remove Linked List Elements
  • Linked List Cycle
  • Linked List Cycle II
  • Reorder List
  • Swap Nodes in Pairs
  • Rotate List
  • Remove Duplicates from Sorted List II
  • Partition List
• Heap
  • Find the Median of a Number Stream (medium)
  • Sliding Window Median (hard)
  • Maximize Capital (hard)
  • Top K Frequent Words
  • Find K Pairs with Smallest Sums
• Stack
  • Longest Valid Paretheses
  • Valid Parentheses
  • 132 Pattern
  • Simplify Path
  • Minimum Add to Make Parentheses Valid
  • Validate Stack Sequences
• Array/String
  • Can Place Flower
  • 1-bit and 2-bit Characters
  • Minimum Index Sum of Two Lists
  • Longest Continuous Increasing Subsequence
  • Median of Two Sorted Arrays
  • Restore IP Addresses
  • Product of Array Except Self
  • Partition Array into Disjoint Intervals
  • Word Subsets
  • Pascal's Triangle
  • Pascal's Triangle II
  • Rotate Image
  • Set Matrix Zeroes
  • Max Increase to Keep City Skyline
  • Sort Array By Parity II
  • Binary Subarrays With Sum
  • Remove Duplicates from Sorted Array II
  • Maximum Average Subarray I
  • Valid Mountain Array
  • Minimum Increment to Make Array Unique
  • Spiral Matrix
  • Spiral Matrix II
• Math
  • Repeated Substring Pattern
  • Range Addition II
  • Largest Triangle Area
  • DI String Match
  • Integer Break
• Sorting Methods
  • Quick Sort
  • Merge Sort
  • Heap Sort
  • Insertion Sort
  • Selection Sort
• Fast & Slow pointers
  • LinkedList Cycle (easy)
  • Start of LinkedList Cycle (medium)
  • Happy Number (medium)
  • Middle of the LinkedList (easy)
• Merge Intervals
  • Merge Intervals (medium)
  • Insert Interval (medium)
  • Intervals Intersection (medium)
  • Conflicting Appointments (medium)
• Cyclic Sort
  • Cyclic Sort (easy)
  • Find the Missing Number (easy)
  • Find all Missing Numbers (easy)
  • Find the Duplicate Number (easy)
  • Find all Duplicate Numbers (easy)
• Top K
  • Top ‘K’ Numbers (easy)
  • Kth Smallest Number (easy)
  • ‘K’ Closest Points to the Origin (easy)
  • Connect Ropes (easy)
  • Top ‘K’ Frequent Numbers (medium)
  • Frequency Sort (medium)
  • Kth Largest Number in a Stream (medium)
  • ‘K’ Closest Numbers (medium)
  • Maximum Distinct Elements (medium)
  • Sum of Elements (medium)
  • Rearrange String (hard)
• K-way Merge
  • Merge K Sorted Lists (medium)
  • Kth Smallest Number in M Sorted Lists (Medium)
  • Kth Smallest Number in a Sorted Matrix (Hard)
  • Smallest Number Range (Hard)
• Topological Sort (Graph)
  • Topological Sort (medium)
  • Tasks Scheduling (medium)
  • Tasks Scheduling Order (medium)
  • All Tasks Scheduling Orders (hard)
  • Alien Dictionary (hard)