NeetCode 450

Arrays & Hashing

• Contains Duplicate (Easy)
• Valid Anagram (Easy)
• Concatenation of Array (Easy)
• Replace Elements With Greatest Element On Right Side (Easy)
• Is Subsequence (Easy)
• Length of Last Word (Easy)
• Two Sum (Easy)
• Longest Common Prefix (Easy)
• Group Anagrams (Medium)
• Pascals Triangle (Easy)
• Remove Element (Easy)
• Unique Email Addresses (Easy)
• Isomorphic Strings (Easy)
• Can Place Flowers (Easy)
• Majority Element (Easy)
• Next Greater Element I (Easy)
• Find Pivot Index (Easy)
• Range Sum Query - Immutable (Easy)
• Find All Numbers Disappeared in An Array (Easy)
• Maximum Number of Balloons (Easy)
• Word Pattern (Easy)
• Design HashSet (Easy)
• Design HashMap (Easy)
• Sort an Array (Medium)
• Top K Frequent Elements (Medium)
• Product of Array Except Self (Medium)
• Valid Sudoku (Medium)
• Encode and Decode Strings   (Medium)
• Longest Consecutive Sequence (Medium)
• Sort Colors (Medium)
• Encode and Decode TinyURL (Medium)
• Brick Wall (Medium)
• Best Time to Buy And Sell Stock II (Medium)
• Subarray Sum Equals K (Medium)
• Unique Length 3 Palindromic Subsequences (Medium)
• Minimum Number of Swaps to Make The String Balanced (Medium)
• Number of Pairs of Interchangeable Rectangles (Medium)
• Maximum Product of The Length of Two Palindromic Subsequences (Medium)
• Grid Game (Medium)
• Find All Anagrams in a String (Medium)
• Find The Index of The First Occurrence in a String (Easy)
• Wiggle Sort   (Medium)
• Largest Number (Medium)
• Continuous Subarray Sum (Medium)
• Push Dominoes (Medium)
• Repeated DNA Sequences (Medium)
• Insert Delete Get Random O(1) (Medium)
• Check if a String Contains all Binary Codes of Size K (Medium)
• Range Sum Query 2D Immutable (Medium)
• Non Decreasing Array (Medium)
• First Missing Positive (Hard)
• Sign of An Array (Easy)
• Find the Difference of Two Arrays (Easy)
• Design Parking System (Easy)
• Number of Zero-Filled Subarrays (Medium)
• Optimal Partition of String (Medium)
• Design Underground System (Medium)
• Minimum Penalty for a Shop (Medium)
• Text Justification (Hard)
• Naming a Company (Hard)

Two Pointers

• Valid Palindrome (Easy)
• Valid Palindrome II (Easy)
• Minimum Difference Between Highest And Lowest of K Scores (Easy)
• Merge Strings Alternately (Easy)
• Reverse String (Easy)
• Merge Sorted Array (Easy)
• Move Zeroes (Easy)
• Remove Duplicates From Sorted Array (Easy)
• Remove Duplicates From Sorted Array II (Medium)
• Two Sum II Input Array Is Sorted (Medium)
• 3Sum (Medium)
• 4Sum (Medium)
• Container With Most Water (Medium)
• Number of Subsequences That Satisfy The Given Sum Condition (Medium)
• Rotate Array (Medium)
• Array With Elements Not Equal to Average of Neighbors (Medium)
• Boats to Save People (Medium)
• Trapping Rain Water (Hard)

Sliding Window

• Best Time to Buy And Sell Stock (Easy)
• Contains Duplicate II (Easy)
• Number of Sub Arrays of Size K and Avg Greater than or Equal to Threshold (Medium)
• Longest Substring Without Repeating Characters (Medium)
• Longest Repeating Character Replacement (Medium)
• Permutation In String (Medium)
• Frequency of The Most Frequent Element (Medium)
• Fruits into Basket (Medium)
• Maximum Number of Vowels in a Substring of Given Length (Medium)
• Minimum Number of Flips to Make The Binary String Alternating (Medium)
• Minimum Size Subarray Sum (Medium)
• Find K Closest Elements (Medium)
• Minimum Operations to Reduce X to Zero (Medium)
• Minimum Window Substring (Hard)
• Sliding Window Maximum (Hard)

Stack

• Valid Parentheses (Easy)
• Baseball Game (Easy)
• Implement Stack Using Queues (Easy)
• Min Stack (Medium)
• Evaluate Reverse Polish Notation (Medium)
• Removing Stars From a String (Medium)
• Validate Stack Sequences (Medium)
• Generate Parentheses (Medium)
• Asteroid Collision (Medium)
• Daily Temperatures (Medium)
• Online Stock Span (Medium)
• Car Fleet (Medium)
• Simplify Path (Medium)
• Decode String (Medium)
• Remove K Digits (Medium)
• Remove All Adjacent Duplicates In String II (Medium)
• 132 Pattern (Medium)
• Maximum Frequency Stack (Hard)
• Largest Rectangle In Histogram (Hard)

Binary Search

• Binary Search (Easy)
• Search Insert Position (Easy)
• Guess Number Higher Or Lower (Easy)
• Arranging Coins (Easy)
• Squares of a Sorted Array (Easy)
• Valid Perfect Square (Easy)
• Sqrt(x) (Easy)
• Single Element in a Sorted Array (Medium)
• Capacity to Ship Packages (Medium)
• Find Peak Element (Medium)
• Successful Pairs of Spells and Potions (Medium)
• Search a 2D Matrix (Medium)
• Koko Eating Bananas (Medium)
• Minimize the Maximum Difference of Pairs (Medium)
• Find Minimum In Rotated Sorted Array (Medium)
• Search In Rotated Sorted Array (Medium)
• Search In Rotated Sorted Array II (Medium)
• Time Based Key Value Store (Medium)
• Find First And Last Position of Element In Sorted Array (Medium)
• Maximum Number of Removable Characters (Medium)
• Populating Next Right Pointers In Each Node (Medium)
• Search Suggestions System (Medium)
• Split Array Largest Sum (Hard)
• Median of Two Sorted Arrays (Hard)

Linked List

• Reverse Linked List (Easy)
• Merge Two Sorted Lists (Easy)
• Palindrome Linked List (Easy)
• Remove Linked List Elements (Easy)
• Remove Duplicates From Sorted List (Easy)
• Middle of the Linked List (Easy)
• Intersection of Two Linked Lists (Easy)
• Reorder List (Medium)
• Maximum Twin Sum Of A Linked List (Medium)
• Remove Nth Node From End of List (Medium)
• Swapping Nodes in a Linked List (Medium)
• LFU Cache (Hard)
• Copy List With Random Pointer (Medium)
• Design Linked List (Medium)
• Design Browser History (Medium)
• Add Two Numbers (Medium)
• Linked List Cycle (Easy)
• Find The Duplicate Number (Medium)
• Swap Nodes In Pairs (Medium)
• Sort List (Medium)
• Partition List (Medium)
• Rotate List (Medium)
• Reverse Linked List II (Medium)
• Design Circular Queue (Medium)
• Insertion Sort List (Medium)
• Split Linked List in Parts (Medium)
• LRU Cache (Medium)
• Merge K Sorted Lists (Hard)
• Reverse Nodes In K Group (Hard)

Trees

• Binary Tree Inorder Traversal (Easy)
• Binary Tree Preorder Traversal (Easy)
• Binary Tree Postorder Traversal (Easy)
• Invert Binary Tree (Easy)
• Maximum Depth of Binary Tree (Easy)
• Diameter of Binary Tree (Easy)
• Balanced Binary Tree (Easy)
• Same Tree (Easy)
• Subtree of Another Tree (Easy)
• Convert Sorted Array to Binary Search Tree (Easy)
• Merge Two Binary Trees (Easy)
• Path Sum (Easy)
• Construct String From Binary Tree (Easy)
• Lowest Common Ancestor of a Binary Search Tree (Medium)
• Insert into a Binary Search Tree (Medium)
• Delete Node in a BST (Medium)
• Binary Tree Level Order Traversal (Medium)
• Binary Tree Right Side View (Medium)
• Minimum Distance between BST Nodes (Easy)
• Symmetric Tree (Easy)
• Minimum Time to Collect All Apples in a Tree (Medium)
• Binary Tree Zigzag Level Order Traversal (Medium)
• Construct Quad Tree (Medium)
• Find Duplicate Subtrees (Medium)
• Check Completeness of a Binary Tree (Medium)
• Construct Binary Tree from Inorder and Postorder Traversal (Medium)
• Maximum Width of Binary Tree (Medium)
• Time Needed to Inform All Employees (Medium)
• Count Good Nodes In Binary Tree (Medium)
• Validate Binary Search Tree (Medium)
• Kth Smallest Element In a Bst (Medium)
• Construct Binary Tree From Preorder And Inorder Traversal (Medium)
• Unique Binary Search Trees (Medium)
• Unique Binary Search Trees II (Medium)
• Sum Root to Leaf Numbers (Medium)
• House Robber III (Medium)
• Flip Equivalent Binary Trees (Medium)
• Operations On Tree (Medium)
• All Possible Full Binary Trees (Medium)
• Find Bottom Left Tree Value (Medium)
• Trim a Binary Search Tree (Medium)
• Binary Search Tree Iterator (Medium)
• Convert Bst to Greater Tree (Medium)
• Binary Tree Maximum Path Sum (Hard)
• Serialize And Deserialize Binary Tree (Hard)

Tries

• Implement Trie Prefix Tree (Medium)
• Design Add And Search Words Data Structure (Medium)
• Extra Characters in a String (Medium)
• Word Search II (Hard)

Heap / Priority Queue

• Kth Largest Element In a Stream (Easy)
• Last Stone Weight (Easy)
• K Closest Points to Origin (Medium)
• Kth Largest Element In An Array (Medium)
• Task Scheduler (Medium)
• Design Twitter (Medium)
• Minimize Deviation in Array (Hard)
• Maximum Subsequence Score (Medium)
• Single Threaded Cpu (Medium)
• Seat Reservation Manager (Medium)
• Process Tasks Using Servers (Medium)
• Find The Kth Largest Integer In The Array (Medium)
• Reorganize String (Medium)
• Longest Happy String (Medium)
• Car Pooling (Medium)
• Find Median From Data Stream (Hard)
• Maximum Performance of a Team (Hard)
• IPO (Hard)

Backtracking

• Subsets (Medium)
• Combination Sum (Medium)
• Combinations (Medium)
• Permutations (Medium)
• Subsets II (Medium)
• Combination Sum II (Medium)
• Permutations II (Medium)
• Word Search (Medium)
• Palindrome Partitioning (Medium)
• Restore IP Addresses (Medium)
• Letter Combinations of a Phone Number (Medium)
• Matchsticks to Square (Medium)
• Splitting a String Into Descending Consecutive Values (Medium)
• Find Unique Binary String (Medium)
• Maximum Length of a Concatenated String With Unique Characters (Medium)
• Partition to K Equal Sum Subsets (Medium)
• N Queens (Hard)
• N Queens II (Hard)

Graphs

• Island Perimeter (Easy)
• Verifying An Alien Dictionary (Easy)
• Number of Islands (Medium)
• Clone Graph (Medium)
• Max Area of Island (Medium)
• Count Sub Islands (Medium)
• Pacific Atlantic Water Flow (Medium)
• Surrounded Regions (Medium)
• Reorder Routes to Make All Paths Lead to The City Zero (Medium)
• Rotting Oranges (Medium)
• Walls And Gates   (Medium)
• Snakes And Ladders (Medium)
• Open The Lock (Medium)
• Find Eventual Safe States (Medium)
• Course Schedule (Medium)
• Course Schedule II (Medium)
• Course Schedule IV (Medium)
• Check if Move Is Legal (Medium)
• Shortest Bridge (Medium)
• Shortest Path in Binary Matrix (Medium)
• Redundant Connection (Medium)
• Number of Connected Components In An Undirected Graph   (Medium)
• Graph Valid Tree   (Medium)
• Accounts Merge (Medium)
• Find Closest Node to Given Two Nodes (Medium)
• As Far from Land as Possible (Medium)
• Shortest Path with Alternating Colors (Medium)
• Minimum Fuel Cost to Report to the Capital (Medium)
• Minimum Score of a Path Between Two Cities (Medium)
• Number of Closed Islands (Medium)
• Number of Enclaves (Medium)
• Minimum Number of Vertices to Reach all Nodes (Medium)
• Is Graph Bipartite? (Medium)
• Evaluate Division (Medium)
• Detonate the Maximum Bombs (Medium)
• Largest Color Value in a Directed Graph (Hard)
• Minimum Number of Days to Eat N Oranges (Hard)
• Word Ladder (Hard)

Advanced Graphs

• Path with Minimum Effort (Medium)
• Reconstruct Itinerary (Hard)
• Min Cost to Connect All Points (Medium)
• Network Delay Time (Medium)
• Path with Maximum Probability (Medium)
• Swim In Rising Water (Hard)
• Alien Dictionary   (Hard)
• Cheapest Flights Within K Stops (Medium)
• Number of Good Paths (Hard)
• Remove Max Number of Edges to Keep Graph Fully Traversable (Hard)
• Find Critical and Pseudo Critical Edges in Minimum Spanning Tree (Hard)

1-D Dynamic Programming

• Climbing Stairs (Easy)
• Min Cost Climbing Stairs (Easy)
• House Robber (Medium)
• House Robber II (Medium)
• Longest Palindromic Substring (Medium)
• Palindromic Substrings (Medium)
• Decode Ways (Medium)
• Coin Change (Medium)
• Maximum Product Subarray (Medium)
• Word Break (Medium)
• Longest Increasing Subsequence (Medium)
• Partition Equal Subset Sum (Medium)
• Triangle (Medium)
• Delete And Earn (Medium)
• Paint House (Medium)
• Combination Sum IV (Medium)
• Perfect Squares (Medium)
• Check if There is a Valid Partition For The Array (Medium)
• Maximum Subarray Min Product (Medium)
• Minimum Cost For Tickets (Medium)
• Integer Break (Medium)
• Number of Longest Increasing Subsequence (Medium)
• Stickers to Spell Word (Hard)
• N-th Tribonacci Number (Easy)
• Uncrossed Lines (Medium)
• Solving Questions With Brainpower (Medium)
• Count Ways to Build Good Strings (Medium)
• New 21 Game (Medium)
• Best Team with no Conflicts (Medium)
• Stone Game III (Hard)
• Concatenated Words (Hard)
• Maximize Score after N Operations (Hard)
• Find the Longest Valid Obstacle Course at Each Position (Hard)
• Count all Valid Pickup and Delivery Options (Hard)

2-D Dynamic Programming

• Unique Paths (Medium)
• Unique Paths II (Medium)
• Longest Common Subsequence (Medium)
• Longest Palindromic Subsequence (Medium)
• Last Stone Weight II (Medium)
• Best Time to Buy And Sell Stock With Cooldown (Medium)
• Coin Change II (Medium)
• Target Sum (Medium)
• Interleaving String (Medium)
• Stone Game (Medium)
• Minimum Path Sum (Medium)
• Longest Increasing Path In a Matrix (Hard)
• Maximal Square (Medium)
• Ones and Zeroes (Medium)
• Maximum Alternating Subsequence Sum (Medium)
• Distinct Subsequences (Hard)
• Edit Distance (Medium)
• Count Vowels Permutation (Hard)
• Burst Balloons (Hard)
• Number of Ways to Rearrange Sticks With K Sticks Visible (Hard)
• Regular Expression Matching (Hard)
• Stone Game II (Medium)
• Flip String to Monotone Increasing (Medium)
• Maximum Value of K Coins from Piles (Hard)
• Number of Music Playlists (Hard)
• Number of Ways to Form a Target String Given a Dictionary (Hard)
• Profitable Schemes (Hard)
• Minimum Cost to Cut a Stick (Hard)

Greedy

• Maximum Subarray (Medium)
• Maximum Sum Circular Subarray (Medium)
• Longest Turbulent Array (Medium)
• Jump Game (Medium)
• Jump Game II (Medium)
• Jump Game VII (Medium)
• Gas Station (Medium)
• Hand of Straights (Medium)
• Minimize Maximum of Array (Medium)
• Dota2 Senate (Medium)
• Maximum Points You Can Obtain From Cards (Medium)
• Merge Triplets to Form Target Triplet (Medium)
• Partition Labels (Medium)
• Valid Parenthesis String (Medium)
• Eliminate Maximum Number of Monsters (Medium)
• Two City Scheduling (Medium)
• Maximum Length of Pair Chain (Medium)
• Minimum Deletions to Make Character Frequencies Unique (Medium)
• Candy (Medium)

Intervals

• Insert Interval (Medium)
• Merge Intervals (Medium)
• Non Overlapping Intervals (Medium)
• Meeting Rooms   (Easy)
• Meeting Rooms II   (Medium)
• Remove Covered Intervals (Medium)
• Minimum Interval to Include Each Query (Hard)
• Data Stream as Disjoint Intervals (Hard)

Math & Geometry

• Excel Sheet Column Title (Easy)
• Greatest Common Divisor of Strings (Easy)
• Count Odd Numbers in an Interval Range (Easy)
• Matrix Diagonal Sum (Easy)
• Maximum Points on a Line (Hard)
• Rotate Image (Medium)
• Spiral Matrix (Medium)
• Spiral Matrix II (Medium)
• Set Matrix Zeroes (Medium)
• Happy Number (Easy)
• Plus One (Easy)
• Palindrome Number (Easy)
• Ugly Number (Easy)
• Shift 2D Grid (Easy)
• Roman to Integer (Easy)
• Integer to Roman (Medium)
• Pow(x, n) (Medium)
• Multiply Strings (Medium)
• Detect Squares (Medium)
• Robot Bounded In Circle (Medium)
• Zigzag Conversion (Medium)
• Find Missing Observations (Medium)

Bit Manipulation

• Single Number (Easy)
• Number of 1 Bits (Easy)
• Counting Bits (Easy)
• Reverse Bits (Easy)
• Missing Number (Easy)
• Shuffle the Array (Easy)
• Add to Array-Form of Integer (Easy)
• Sum of Two Integers (Medium)
• Reverse Integer (Medium)
• Add Binary (Easy)

JavaScript

• Create Hello World Function (Easy)
• Counter (Easy)
• Counter II (Easy)
• Apply Transform over each Element in Array (Easy)
• Filter Elements from Array (Easy)
• Array Reduce Transformation (Easy)
• Function Composition (Easy)
• Allow One Function Call (Easy)
• Memoize (Medium)
• Curry (Medium)
• Sleep (Easy)
• Promise Time Limit (Easy)
• Promise Pool (Medium)
• Cache With Time Limit (Medium)
• Debounce (Medium)
• Throttle (Medium)
• JSON Deep Equal (Medium)
• Convert Object to JSON String (Medium)
• Array of Objects to Matrix (Medium)
• Difference Between Two Objects (Medium)
• Chunk Array (Easy)
• Flatten Deeply Nested Array (Medium)
• Array Prototype Last (Easy)
• Group By (Medium)
• Check if Object Instance of Class (Medium)
• Call Function with Custom Context (Medium)
• Event Emitter (Medium)
• Array Wrapper (Easy)
• Generate Fibonacci Sequence (Easy)
• Nested Array Generator (Medium)