Problem Index

All problems from the Blind 75, Grind 75, Grind 169, NeetCode 150, Amazon Top 50, and Google Top 50 lists. Problems marked 🔒 require a LeetCode Premium subscription.

Use the dropdowns to filter by difficulty, pattern, list, or status.

Problem	Difficulty	Pattern	Lists	Status
Two Sum	🟢 Easy	Array, Hash Table	Blind 75, Grind 75, Grind 169, NeetCode 150, Google Top 50	✅ Covered
Contains Duplicate	🟢 Easy	Array, Hash Table, Sorting	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
Valid Anagram	🟢 Easy	Hash Table, String, Sorting	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
Ransom Note	🟢 Easy	Hash Table, String, Counting	Grind 75, Grind 169	✅ Covered
Majority Element	🟢 Easy	Array, Hash Table, Divide and Conquer, Sorting, Counting	Grind 75, Grind 169	✅ Covered
Longest Palindrome			Grind 75, Grind 169	⬜ Missing
Group Anagrams	🟡 Medium	Array, Hash Table, String, Sorting	Blind 75, Grind 169, NeetCode 150, Amazon Top 50	✅ Covered
Top K Frequent Elements	🟡 Medium	Array, Hash Table, Divide and Conquer, Sorting, Heap (Priority Queue)	Blind 75, NeetCode 150, Google Top 50	✅ Covered
Product of Array Except Self	🟡 Medium	Array, Prefix Sum	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
Encode and Decode Strings	🟡 Medium	Array, String, Design	Blind 75, Grind 169, NeetCode 150	✅ Covered
Longest Consecutive Sequence	🟡 Medium	Array, Hash Table, Union-Find	Blind 75, Grind 169, NeetCode 150	✅ Covered
Valid Sudoku	🟡 Medium	Array, Hash Table, Matrix	Grind 169, NeetCode 150	✅ Covered
Valid Palindrome	🟢 Easy	Two Pointers, String	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
3Sum	🟡 Medium	Array, Two Pointers, Sorting	Blind 75, Grind 75, Grind 169, NeetCode 150, Google Top 50	✅ Covered
Container With Most Water	🟡 Medium	Array, Two Pointers, Greedy	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
Sort Colors			Grind 75, Grind 169	⬜ Missing
Two Sum II	🟡 Medium	Array, Two Pointers, Binary Search	NeetCode 150	✅ Covered
Trapping Rain Water	🔴 Hard	Array, Two Pointers, Dynamic Programming, Stack, Monotonic Stack	Grind 75, Grind 169, NeetCode 150, Amazon Top 50, Google Top 50	✅ Covered
Best Time to Buy and Sell Stock	🟢 Easy	Array, Dynamic Programming	Blind 75, Grind 75, Grind 169, NeetCode 150, Google Top 50	✅ Covered
Longest Substring Without Repeating Characters	🟡 Medium	Hash Table, String, Sliding Window	Blind 75, Grind 75, Grind 169, NeetCode 150, Google Top 50	✅ Covered
Find All Anagrams in a String			Grind 75, Grind 169	⬜ Missing
Longest Repeating Character Replacement			Blind 75, Grind 169, NeetCode 150	⬜ Missing
Minimum Window Substring	🔴 Hard	Hash Table, String, Sliding Window	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
Permutation in String	🟡 Medium	Hash Table, Two Pointers, String, Sliding Window	NeetCode 150	✅ Covered
Sliding Window Maximum	🔴 Hard	Array, Queue, Sliding Window, Heap (Priority Queue), Monotonic Queue	Grind 169, NeetCode 150, Amazon Top 50	✅ Covered
Valid Parentheses	🟢 Easy	String, Stack	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
Implement Queue using Stacks			Grind 75, Grind 169	⬜ Missing
Min Stack	🟡 Medium	Stack, Design	Grind 75, Grind 169, NeetCode 150	✅ Covered
Evaluate Reverse Polish Notation	🟡 Medium	Array, Math, Stack	Grind 75, Grind 169, NeetCode 150, Google Top 50	✅ Covered
Basic Calculator			Grind 75, Grind 169, Google Top 50	⬜ Missing
Generate Parentheses	🟡 Medium	String, Dynamic Programming, Backtracking	Grind 169, NeetCode 150	✅ Covered
Daily Temperatures	🟡 Medium	Array, Stack, Monotonic Stack	Grind 169, NeetCode 150	✅ Covered
Car Fleet	🟡 Medium	Array, Stack, Sorting, Monotonic Stack	NeetCode 150	✅ Covered
Largest Rectangle in Histogram			Grind 75, Grind 169, NeetCode 150	⬜ Missing
Binary Search	🟢 Easy	Array, Binary Search	Grind 75, Grind 169, NeetCode 150	✅ Covered
First Bad Version			Grind 75, Grind 169, Google Top 50	⬜ Missing
Find Minimum in Rotated Sorted Array	🟡 Medium	Array, Binary Search	Blind 75, Grind 169, NeetCode 150	✅ Covered
Search in Rotated Sorted Array	🟡 Medium	Array, Binary Search	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
Search a 2D Matrix	🟡 Medium	Array, Binary Search, Matrix	Grind 169, NeetCode 150	✅ Covered
Koko Eating Bananas	🟡 Medium	Array, Binary Search	NeetCode 150	✅ Covered
Time Based Key-Value Store	🟡 Medium	Hash Table, String, Binary Search, Design	Grind 75, Grind 169, NeetCode 150	✅ Covered
Median of Two Sorted Arrays			Grind 169, NeetCode 150, Google Top 50	⬜ Missing
Reverse Linked List	🟢 Easy	Linked List, Recursion	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
Merge Two Sorted Lists	🟢 Easy	Linked List, Recursion	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
Middle of the Linked List			Grind 75, Grind 169	⬜ Missing
Reorder List	🟡 Medium	Linked List, Two Pointers, Stack, Recursion	Blind 75, Grind 169, NeetCode 150	✅ Covered
Remove Nth Node From End of List	🟡 Medium	Linked List, Two Pointers	Blind 75, Grind 169, NeetCode 150	✅ Covered
Merge K Sorted Lists	🔴 Hard	Linked List, Divide and Conquer, Heap (Priority Queue), Merge Sort	Blind 75, Grind 75, Grind 169, NeetCode 150, Google Top 50	✅ Covered
Linked List Cycle	🟢 Easy	Hash Table, Linked List, Two Pointers	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
Add Two Numbers	🟡 Medium	Linked List, Math, Recursion	Grind 169, NeetCode 150, Google Top 50	✅ Covered
Copy List With Random Pointer	🟡 Medium	Hash Table, Linked List	NeetCode 150, Amazon Top 50	✅ Covered
Find the Duplicate Number	🟡 Medium	Array, Two Pointers, Binary Search, Bit Manipulation	Grind 169, NeetCode 150	✅ Covered
LRU Cache	🟡 Medium	Hash Table, Linked List, Design, Doubly-Linked List	Grind 75, Grind 169, NeetCode 150, Amazon Top 50, Google Top 50	✅ Covered
Reverse Nodes in K Group			Grind 169, NeetCode 150	⬜ Missing
Invert Binary Tree	🟢 Easy	Tree, Depth-First Search, Breadth-First Search, Binary Tree	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
Maximum Depth of Binary Tree	🟢 Easy	Tree, Depth-First Search, Breadth-First Search, Binary Tree	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
Diameter of Binary Tree	🟢 Easy	Tree, Depth-First Search, Binary Tree	Grind 75, Grind 169, NeetCode 150	✅ Covered
Balanced Binary Tree	🟢 Easy	Tree, Depth-First Search, Binary Tree	Grind 75, Grind 169, NeetCode 150	✅ Covered
Same Tree	🟢 Easy	Tree, Depth-First Search, Breadth-First Search, Binary Tree	Blind 75, Grind 169, NeetCode 150	✅ Covered
Subtree of Another Tree	🟢 Easy	Tree, Depth-First Search, String Matching, Binary Tree, Hash Function	Blind 75, Grind 169, NeetCode 150	✅ Covered
Lowest Common Ancestor of a BST	🟡 Medium	Tree, Depth-First Search, Binary Search Tree, Binary Tree	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
Lowest Common Ancestor of Binary Tree			Grind 75, Grind 169	⬜ Missing
Binary Tree Level Order Traversal	🟡 Medium	Tree, Breadth-First Search, Binary Tree	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
Binary Tree Right Side View	🟡 Medium	Tree, Depth-First Search, Breadth-First Search, Binary Tree	Grind 75, Grind 169, NeetCode 150	✅ Covered
Validate Binary Search Tree	🟡 Medium	Tree, Depth-First Search, Binary Search Tree, Binary Tree	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
Kth Smallest Element in a BST	🟡 Medium	Tree, Depth-First Search, Binary Search Tree, Binary Tree	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
Construct Binary Tree from Preorder and Inorder Traversal	🟡 Medium	Array, Hash Table, Divide and Conquer, Tree, Binary Tree	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
Binary Tree Maximum Path Sum			Blind 75, Grind 169, NeetCode 150	⬜ Missing
Serialize and Deserialize Binary Tree			Blind 75, Grind 75, Grind 169, NeetCode 150	⬜ Missing
Count Good Nodes in Binary Tree	🟡 Medium	Tree, Depth-First Search, Breadth-First Search, Binary Tree	NeetCode 150	✅ Covered
Implement Trie (Prefix Tree)	🟡 Medium	Hash Table, String, Design, Trie	Blind 75, Grind 75, Grind 169, NeetCode 150, Google Top 50	✅ Covered
Design Add and Search Words	🟡 Medium	String, Depth-First Search, Design, Trie	Blind 75, Grind 169, NeetCode 150	✅ Covered
Word Search II			Blind 75, Grind 169, NeetCode 150	⬜ Missing
Find Median from Data Stream			Blind 75, Grind 75, Grind 169, NeetCode 150, Amazon Top 50	⬜ Missing
K Closest Points to Origin			Grind 75, Grind 169, NeetCode 150, Amazon Top 50	⬜ Missing
Task Scheduler			Grind 75, Grind 169, NeetCode 150	⬜ Missing
Kth Largest Element in a Stream	🟢 Easy	Tree, Design, Binary Search Tree, Heap (Priority Queue), Binary Tree, Data Stream	NeetCode 150	✅ Covered
Last Stone Weight	🟢 Easy	Array, Heap (Priority Queue)	NeetCode 150	✅ Covered
Kth Largest Element in an Array			Grind 169, NeetCode 150	⬜ Missing
Design Twitter			NeetCode 150	⬜ Missing
Combination Sum	🟡 Medium	Array, Backtracking	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
Word Search	🟡 Medium	Array, String, Backtracking, Depth-First Search, Matrix	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
Subsets	🟡 Medium	Array, Backtracking, Bit Manipulation	Grind 75, Grind 169, NeetCode 150	✅ Covered
Permutations	🟡 Medium	Array, Backtracking	Grind 75, Grind 169, NeetCode 150	✅ Covered
Letter Combinations of a Phone Number	🟡 Medium	Hash Table, String, Backtracking	Grind 75, Grind 169, NeetCode 150	✅ Covered
Subsets II	🟡 Medium	Array, Backtracking, Bit Manipulation	NeetCode 150	✅ Covered
Combination Sum II	🟡 Medium	Array, Backtracking	NeetCode 150	✅ Covered
Palindrome Partitioning	🟡 Medium	String, Dynamic Programming, Backtracking	NeetCode 150	✅ Covered
N-Queens			Grind 169, NeetCode 150	⬜ Missing
Number of Islands	🟡 Medium	Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix	Blind 75, Grind 75, Grind 169, NeetCode 150, Amazon Top 50, Google Top 50	✅ Covered
Flood Fill			Grind 75, Grind 169	⬜ Missing
01 Matrix			Grind 75, Grind 169	⬜ Missing
Clone Graph	🟡 Medium	Hash Table, Depth-First Search, Breadth-First Search, Graph Theory	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
Rotting Oranges	🟡 Medium	Array, Breadth-First Search, Matrix	Grind 75, Grind 169, NeetCode 150, Amazon Top 50	✅ Covered
Accounts Merge			Grind 75, Grind 169	⬜ Missing
Minimum Height Trees			Grind 75, Grind 169	⬜ Missing
Pacific Atlantic Water Flow			Blind 75, Grind 169, NeetCode 150, Google Top 50	⬜ Missing
Course Schedule	🟡 Medium	Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort	Blind 75, Grind 75, Grind 169, NeetCode 150, Amazon Top 50	✅ Covered
Graph Valid Tree			Blind 75, Grind 169, NeetCode 150	🔒 Premium
Number of Connected Components			Blind 75, Grind 169, NeetCode 150	🔒 Premium
Max Area of Island	🟡 Medium	Array, Depth-First Search, Breadth-First Search, Union-Find, Matrix	NeetCode 150, Google Top 50	✅ Covered
Surrounded Regions			NeetCode 150	⬜ Missing
Walls and Gates	🟡 Medium	Array, Breadth-First Search, Matrix	NeetCode 150	✅ Covered
Course Schedule II	🟡 Medium	Depth-First Search, Breadth-First Search, Graph Theory, Topological Sort	Grind 169, NeetCode 150, Google Top 50	✅ Covered
Redundant Connection			NeetCode 150	⬜ Missing
Word Ladder			Grind 75, Grind 169, NeetCode 150, Amazon Top 50	⬜ Missing
Alien Dictionary			Blind 75, Grind 169, NeetCode 150	🔒 Premium
Reconstruct Itinerary			NeetCode 150	⬜ Missing
Min Cost to Connect All Points	🟡 Medium	Array, Union-Find, Graph Theory, Minimum Spanning Tree	NeetCode 150	✅ Covered
Network Delay Time	🟡 Medium	Depth-First Search, Breadth-First Search, Graph Theory, Heap (Priority Queue), Shortest Path	NeetCode 150	✅ Covered
Swim in Rising Water			NeetCode 150	⬜ Missing
Cheapest Flights Within K Stops	🟡 Medium	Dynamic Programming, Depth-First Search, Breadth-First Search, Graph Theory, Heap (Priority Queue)	Grind 169, NeetCode 150	✅ Covered
Climbing Stairs	🟢 Easy	Math, Dynamic Programming, Memoization	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
House Robber	🟡 Medium	Array, Dynamic Programming	Blind 75, Grind 169, NeetCode 150	✅ Covered
House Robber II	🟡 Medium	Array, Dynamic Programming	Blind 75, NeetCode 150, Google Top 50	✅ Covered
Longest Palindromic Substring	🟡 Medium	Two Pointers, String, Dynamic Programming	Blind 75, Grind 75, Grind 169, NeetCode 150, Google Top 50	✅ Covered
Decode Ways	🟡 Medium	String, Dynamic Programming	Blind 75, Grind 169, NeetCode 150	✅ Covered
Coin Change			Blind 75, Grind 75, Grind 169, NeetCode 150	⬜ Missing
Maximum Product Subarray	🟡 Medium	Array, Dynamic Programming	Blind 75, Grind 169, NeetCode 150	✅ Covered
Word Break	🟡 Medium	Array, Hash Table, String, Dynamic Programming, Trie	Blind 75, Grind 75, Grind 169, NeetCode 150	✅ Covered
Longest Increasing Subsequence			Blind 75, Grind 169, NeetCode 150	⬜ Missing
Palindromic Substrings	🟡 Medium	Two Pointers, String, Dynamic Programming	Blind 75, NeetCode 150	✅ Covered
Min Cost Climbing Stairs	🟢 Easy	Array, Dynamic Programming	NeetCode 150	✅ Covered
Partition Equal Subset Sum	🟡 Medium	Array, Dynamic Programming	Grind 75, Grind 169, NeetCode 150	✅ Covered
Unique Paths	🟡 Medium	Math, Dynamic Programming, Combinatorics	Blind 75, Grind 75, Grind 169, NeetCode 150, Google Top 50	✅ Covered
Longest Common Subsequence	🟡 Medium	String, Dynamic Programming	Blind 75, NeetCode 150	✅ Covered
Maximum Profit in Job Scheduling			Grind 75, Grind 169	⬜ Missing
Regular Expression Matching			NeetCode 150, Google Top 50	⬜ Missing
Best Time to Buy and Sell Stock with Cooldown			NeetCode 150	⬜ Missing
Coin Change II			NeetCode 150	⬜ Missing
Target Sum	🟡 Medium	Array, Dynamic Programming, Backtracking	NeetCode 150	✅ Covered
Interleaving String			NeetCode 150	⬜ Missing
Longest Increasing Path in a Matrix			Grind 169, NeetCode 150	⬜ Missing
Distinct Subsequences			NeetCode 150	⬜ Missing
Edit Distance	🟡 Medium	String, Dynamic Programming	NeetCode 150	✅ Covered
Burst Balloons			NeetCode 150	⬜ Missing
Maximum Subarray	🟡 Medium	Array, Divide and Conquer, Dynamic Programming	Blind 75, Grind 75, Grind 169, NeetCode 150, Google Top 50	✅ Covered
Jump Game	🟡 Medium	Array, Dynamic Programming, Greedy	Blind 75, Grind 169, NeetCode 150	✅ Covered
Gas Station	🟡 Medium	Array, Greedy	Grind 169, NeetCode 150	✅ Covered
Jump Game II			NeetCode 150	⬜ Missing
Hand of Straights			NeetCode 150	⬜ Missing
Merge Triplets to Form Target Triplet			NeetCode 150	⬜ Missing
Partition Labels			NeetCode 150	⬜ Missing
Valid Parenthesis String			NeetCode 150	⬜ Missing
Insert Interval			Blind 75, Grind 75, Grind 169, NeetCode 150, Google Top 50	⬜ Missing
Merge Intervals	🟡 Medium	Array, Sorting	Blind 75, Grind 75, Grind 169, NeetCode 150, Google Top 50	✅ Covered
Non-overlapping Intervals			Blind 75, Grind 169, NeetCode 150	⬜ Missing
Meeting Rooms			Blind 75, Grind 169, NeetCode 150	🔒 Premium
Meeting Rooms II			Blind 75, Grind 169, NeetCode 150, Amazon Top 50, Google Top 50	🔒 Premium
Minimum Interval to Include Each Query			NeetCode 150	⬜ Missing
Rotate Image	🟡 Medium	Array, Math, Matrix	Blind 75, Grind 169, NeetCode 150	✅ Covered
Spiral Matrix			Blind 75, Grind 75, Grind 169, NeetCode 150	⬜ Missing
Set Matrix Zeroes	🟡 Medium	Array, Hash Table, Matrix	Blind 75, Grind 169, NeetCode 150	✅ Covered
Add Binary	🟢 Easy	Math, String, Bit Manipulation, Simulation	Grind 75, Grind 169	✅ Covered
String to Integer (atoi)	🟡 Medium	String	Grind 75, Grind 169	✅ Covered
Happy Number	🟢 Easy	Hash Table, Math, Two Pointers	NeetCode 150, Google Top 50	✅ Covered
Plus One	🟢 Easy	Array, Math	NeetCode 150	✅ Covered
Pow(x, n)	🟡 Medium	Math, Recursion	Grind 169, NeetCode 150	✅ Covered
Multiply Strings			NeetCode 150	⬜ Missing
Detect Squares			NeetCode 150	⬜ Missing
Sum of Two Integers			Blind 75, NeetCode 150	⬜ Missing
Number of 1 Bits			Blind 75, Grind 169, NeetCode 150	⬜ Missing
Counting Bits			Blind 75, Grind 169, NeetCode 150	⬜ Missing
Reverse Bits			Blind 75, Grind 169, NeetCode 150	⬜ Missing
Missing Number	🟢 Easy	Array, Hash Table, Math, Binary Search, Bit Manipulation, Sorting	Blind 75, Grind 169, NeetCode 150	✅ Covered
Single Number			Grind 169, NeetCode 150	⬜ Missing
Reverse Integer	🟡 Medium	Math	Grind 169, NeetCode 150	✅ Covered
Move Zeroes			Grind 169	⬜ Missing
Squares of a Sorted Array			Grind 169	⬜ Missing
Rotate Array			Grind 169	⬜ Missing
Contiguous Array			Grind 169	⬜ Missing
Subarray Sum Equals K			Grind 169, Google Top 50	⬜ Missing
3Sum Closest			Grind 169	⬜ Missing
Maximal Square			Grind 169	⬜ Missing
Combination Sum IV			Grind 169	⬜ Missing
Shortest Path to Get Food			Grind 169	🔒 Premium
Minimum Knight Moves			Grind 169	🔒 Premium
Bus Routes			Grind 169	⬜ Missing
Employee Free Time			Grind 169	🔒 Premium
Palindrome Linked List	🟢 Easy	Linked List, Two Pointers, Stack, Recursion	Grind 169	✅ Covered
Swap Nodes in Pairs			Grind 169	⬜ Missing
Odd Even Linked List			Grind 169	⬜ Missing
Sort List	🟡 Medium	Linked List, Two Pointers, Divide and Conquer, Sorting, Merge Sort	Grind 169	✅ Covered
Rotate List			Grind 169	⬜ Missing
Sudoku Solver			Grind 169	⬜ Missing
Backspace String Compare			Grind 169	⬜ Missing
Decode String			Grind 169, Google Top 50	⬜ Missing
Asteroid Collision			Grind 169	⬜ Missing
Basic Calculator II			Grind 169	⬜ Missing
Maximum Frequency Stack			Grind 169	⬜ Missing
Longest Valid Parentheses			Grind 169	⬜ Missing
Longest Common Prefix	🟢 Easy	Array, String, Trie	Grind 169, Google Top 50	✅ Covered
Largest Number			Grind 169	⬜ Missing
Palindrome Pairs			Grind 169	⬜ Missing
Convert Sorted Array to Binary Search Tree	🟢 Easy	Array, Divide and Conquer, Tree, Binary Search Tree, Binary Tree	Grind 169	✅ Covered
Symmetric Tree	🟢 Easy	Tree, Depth-First Search, Breadth-First Search, Binary Tree	Grind 169	✅ Covered
Path Sum II			Grind 169	⬜ Missing
Maximum Width of Binary Tree			Grind 169	⬜ Missing
Binary Tree Zigzag Level Order Traversal	🟡 Medium	Tree, Breadth-First Search, Binary Tree	Grind 169	✅ Covered
Path Sum III			Grind 169	⬜ Missing
All Nodes Distance K in Binary Tree			Grind 169, Amazon Top 50	⬜ Missing
Inorder Successor in BST			Grind 169	🔒 Premium
Design Hit Counter			Grind 169	🔒 Premium
Design In-Memory File System			Grind 169, Amazon Top 50	🔒 Premium
Insert Delete GetRandom O(1)	🟡 Medium	Array, Hash Table, Math, Design, Randomized	Grind 169	✅ Covered
First Missing Positive			Grind 169	⬜ Missing
Top K Frequent Words			Grind 169	⬜ Missing
Find K Closest Elements			Grind 169	⬜ Missing
Smallest Range Covering Elements from K Lists			Grind 169	⬜ Missing
Next Permutation			Grind 169	⬜ Missing
Roman to Integer	🟢 Easy	Hash Table, Math, String	Grind 169, Google Top 50	✅ Covered
Palindrome Number	🟢 Easy	Math	Grind 169, Google Top 50	✅ Covered
Random Pick with Weight			Grind 169, Google Top 50	⬜ Missing
Integer to Roman	🟡 Medium	Hash Table, Math, String		✅ Covered
Find the Index of the First Occurrence in a String	🟢 Easy	Two Pointers, String, String Matching		✅ Covered
Compare Version Numbers				⬜ Missing
Integer to English Words			Amazon Top 50	⬜ Missing
First Unique Character in a String	🟢 Easy	Hash Table, String, Queue, Counting		✅ Covered
Most Common Word				⬜ Missing
Reorder Data in Log Files			Amazon Top 50	⬜ Missing
Word Ladder II				⬜ Missing
Cut Off Trees for Golf Event				⬜ Missing
Design Tic-Tac-Toe			Amazon Top 50	🔒 Premium
Design Search Autocomplete System			Google Top 50	🔒 Premium
Prison Cells After N Days				⬜ Missing
Battleships in a Board			Google Top 50	⬜ Missing
Bulls and Cows			Google Top 50	⬜ Missing
Find Duplicate Subtrees			Google Top 50	⬜ Missing
Find Leaves of Binary Tree			Google Top 50	🔒 Premium
Find Original Array From Doubled Array			Google Top 50	⬜ Missing
Find Winner on a Tic Tac Toe Game			Google Top 50	⬜ Missing
H-Index	🟡 Medium	Array, Sorting, Counting Sort	Google Top 50	✅ Covered
Logger Rate Limiter			Google Top 50	🔒 Premium
Maximum Points You Can Obtain from Cards			Google Top 50	⬜ Missing
Minimum Time Difference			Google Top 50	⬜ Missing
Number of Matching Subsequences			Google Top 50	⬜ Missing
Snapshot Array			Google Top 50	⬜ Missing
Stock Price Fluctuation			Google Top 50	⬜ Missing
Student Attendance Record II			Google Top 50	⬜ Missing
Text Justification			Google Top 50	⬜ Missing
Time Needed to Inform All Employees			Google Top 50	⬜ Missing
Analyze User Website Visit Pattern			Amazon Top 50	🔒 Premium
Boundary of Binary Tree			Amazon Top 50	🔒 Premium
Build Binary Expression Tree From Infix Expression			Amazon Top 50	🔒 Premium
Concatenated Words			Amazon Top 50	⬜ Missing
Count Unique Characters of All Substrings of a Given String			Amazon Top 50	⬜ Missing
Design an Expression Tree With Evaluate Function			Amazon Top 50	🔒 Premium
Design Parking System			Amazon Top 50	⬜ Missing
Find Good Days to Rob the Bank			Amazon Top 50	⬜ Missing
Find K-th Smallest Pair Distance			Amazon Top 50	⬜ Missing
Find the K-Sum of an Array			Amazon Top 50	⬜ Missing
Find Triangular Sum of an Array			Amazon Top 50	⬜ Missing
Make Array Zero by Subtracting Equal Amounts			Amazon Top 50	⬜ Missing
Maximum Length of Subarray With Positive Product			Amazon Top 50	⬜ Missing
Maximum Number of Books You Can Take			Amazon Top 50	🔒 Premium
Maximum Number of Robots Within Budget			Amazon Top 50	⬜ Missing
Maximum Units on a Truck			Amazon Top 50	⬜ Missing
Minimum Adjacent Swaps to Make a Valid Array			Amazon Top 50	⬜ Missing
Minimum Health to Beat Game			Amazon Top 50	🔒 Premium
Minimum Number of Keypresses			Amazon Top 50	🔒 Premium
Minimum Number of Moves to Make Palindrome			Amazon Top 50	⬜ Missing
Minimum Number of Swaps to Make the Binary String Alternating			Amazon Top 50	⬜ Missing
Number of Ways to Select Buildings			Amazon Top 50	⬜ Missing
Plates Between Candles			Amazon Top 50	⬜ Missing
Race Car			Amazon Top 50	⬜ Missing
Reorganize String			Amazon Top 50	⬜ Missing
Search Suggestions System			Amazon Top 50	⬜ Missing
Sequential Digits			Amazon Top 50	⬜ Missing
Sequentially Ordinal Rank Tracker			Amazon Top 50	⬜ Missing
Substring With Largest Variance			Amazon Top 50	⬜ Missing
Sum of Subarray Ranges			Amazon Top 50	⬜ Missing
Sum of Total Strength of Wizards			Amazon Top 50	⬜ Missing
Total Appeal of A String			Amazon Top 50	⬜ Missing
Word Break II			Amazon Top 50	⬜ Missing