What is NeetCode 150?

Neetcode 150 is a curated list of 150 LeetCode problems designed to cover all topics in data structures. It is an invaluable resource to study for LeetCode-style interviews you might enounter at FAANG and other big tech companies. There are several categories of questions and inside each category are easy, medium, and hard questions.

Creator's original repository and website.

Below is a list of my solutions for all the problems in C++, Python and Rust.

To contribute, see here.

Arrays & Hashing

LeetCode ID	Difficulty	Problem	Solution
217	Easy	Contains Duplicate	C++ • Python • Rust
242	Easy	Valid Anagram	C++ • Python • Rust
1	Easy	Two Sum	C++ • Python • Rust
49	Medium	Group Anagrams	C++ • Python • Rust
347	Medium	Top K Frequent Elements	C++ • Python • Rust
238	Medium	Product of Array Except Self	C++ • Python • Rust
36	Medium	Valid Sudoku	C++ • Python • Rust
271	Medium	Encode and Decode Strings	C++ • Python • Rust
128	Medium	Longest Consecutive Sequence	C++ • Python • Rust

Two Pointers

LeetCode ID	Difficulty	Problem	Solution
125	Easy	Valid Palindrome	C++ • Python • Rust
167	Medium	Two Sum II	C++ • Python • Rust
15	Medium	3Sum	C++ • Python • Rust
11	Medium	Container with Most Water	C++ • Python • Rust
42	Hard	Trapping Rain Water	C++ • Python • Rust

Sliding Window

LeetCode ID	Difficulty	Problem	Solution
121	Easy	Best Time to Buy & Sell Stock	C++ • Python • Rust
3	Medium	Longest Substring Without Repeating Characters	C++ • Python • Rust
424	Medium	Longest Repeating Character Replacement	C++ • Python • Rust
567	Medium	Permutation in String	C++ • Python • Rust
76	Hard	Minimum Window Substring	C++ • Python • Rust
239	Hard	Sliding Window Maximum	C++ • Python • Rust

Stack

LeetCode ID	Difficulty	Problem	Solution
20	Easy	Valid Parentheses	C++ • Python • Rust
155	Medium	Min Stack	C++ • Python • Rust
150	Medium	Evaluate Reverse Polish Notation	C++ • Python • Rust
22	Medium	Generate Parentheses	C++ • Python • Rust
739	Medium	Daily Temperatures	C++ • Python • Rust
853	Medium	Car Fleet	C++ • Python • Rust
84	Hard	Largest Rectangle in Histogram	C++ • Python • Rust

Binary Search

LeetCode ID	Difficulty	Problem	Solution
704	Easy	Binary Search	C++ • Python • Rust
74	Medium	Search a 2D Matrix	C++ • Python • Rust
875	Medium	Koko Eating Bananas	C++ • Python • Rust
33	Medium	Search in Rotated Sorted Array	C++ • Python • Rust
153	Medium	Find Minimum in Rotated Sorted Array	C++ • Python • Rust
981	Medium	Time Based Key-Value Store	C++ • Python • Rust
4	Hard	Median of Two Sorted Arrays	C++ • Python • Rust

Linked List

LeetCode ID	Difficulty	Problem	Solution
206	Easy	Reverse Linked List	C++ • Python • Rust
21	Easy	Merge Two Sorted Lists	C++ • Python • Rust
143	Medium	Reorder List	C++ • Python • Rust
19	Medium	Remove Nth Node From End of List	C++ • Python • Rust
141	Easy	Copy List with Random Pointer	C++ • Python • Rust
2	Medium	Add Two Numbers	C++ • Python • Rust
141	Easy	Linked List Cycle	C++ • Python • Rust
287	Medium	Find the Duplicate Number	C++ • Python • Rust
146	Medium	LRU Cache	C++ • Python • Rust
23	Hard	Merge k Sorted Lists	C++ • Python • Rust
25	Hard	Reverse Nodes in k-Group	C++ • Python • Rust

Trees

LeetCode ID	Difficulty	Problem	Solution
226	Easy	Invert Binary Tree	C++ • Python • Rust
104	Easy	Maximum Depth of Binary Tree	C++ • Python • Rust
543	Easy	Diameter of Binary Tree	C++ • Python • Rust
110	Easy	Balanced Binary Tree	C++ • Python • Rust
100	Easy	Same Tree	C++ • Python • Rust
572	Easy	Subtree Of Another Tree	C++ • Python • Rust
235	Medium	Lowest Common Ancestor Of A Binary Search Tree	C++ • Python • Rust
102	Medium	Binary Tree Level Order Traversal	C++ • Python • Rust
199	Medium	Binary Tree Right Side View	C++ • Python • Rust
1448	Medium	Count Good Nodes in Binary Tree	C++ • Python • Rust
98	Medium	Validate Binary Search Tree	C++ • Python • Rust
230	Medium	Kth Smallest Element in a BST	C++ • Python • Rust
105	Medium	Construct Binary Tree from Preorder and Inorder Traversal	C++ • Python • Rust
124	Hard	Binary Tree Maximum Path Sum	C++ • Python • Rust
297	Hard	Serialize and Deserialize Binary Tree	C++ • Python • Rust

Tries

LeetCode ID	Difficulty	Problem	Solution
208	Medium	Implement Trie (Prefix Tree)	C++ • Python • Rust
211	Medium	Design Add and Search Words Data Structure	C++ • Python • Rust
212	Hard	Word Search II	C++ • Python • Rust

Heap / Priority Queue

LeetCode ID	Difficulty	Problem	Solution
703	Easy	Kth Largest Element in a Stream	C++ • Python • Rust
1046	Easy	Last Stone Weight	C++ • Python • Rust
973	Medium	K Closest Points to Origin	C++ • Python • Rust
215	Medium	Kth Largest Element in an Array	C++ • Python • Rust
621	Medium	Task Scheduler	C++ • Python • Rust
355	Medium	Design Twitter	C++ • Python • Rust
295	Hard	Find Median from Data Stream	C++ • Python • Rust

Backtracking

LeetCode ID	Difficulty	Problem	Solution
78	Medium	Subsets	C++ • Python • Rust
39	Medium	Combination Sum	C++ • Python • Rust
46	Medium	Permutations	C++ • Python • Rust
90	Medium	Subsets II	C++ • Python • Rust
40	Medium	Combination Sum II	C++ • Python • Rust
79	Medium	Word Search	C++ • Python • Rust
131	Medium	Palindrome Partitioning	C++ • Python • Rust
17	Medium	Letter Combinations of a Phone Number	C++ • Python • Rust
51	Hard	N-Queens	C++ • Python • Rust

Graphs

LeetCode ID	Difficulty	Problem	Solution
200	Medium	Number of Islands	C++ • Python • Rust
133	Medium	Clone Graph	C++ • Python • Rust
695	Medium	Max Area of Island	C++ • Python • Rust
417	Medium	Pacific Atlantic Water Flow	C++ • Python • Rust
130	Medium	Surrounded Regions	C++ • Python • Rust
994	Medium	Rotting Oranges	C++ • Python • Rust
286	Medium	Walls and Gates	C++ • Python • Rust
207	Medium	Course Schedule	C++ • Python • Rust
210	Medium	Course Schedule II	C++ • Python • Rust
684	Medium	Redundant Connection	C++ • Python • Rust
323	Medium	Number of Connected Components In An Undirected Graph	C++ • Python • Rust
261	Medium	Graph Valid Tree	C++ • Python • Rust
127	Hard	Word Ladder	C++ • Python • Rust

Advanced Graphs

LeetCode ID	Difficulty	Problem	Solution
332	Hard	Reconstruct Itinerary	C++ • Python • Rust
1584	Medium	Min Cost to Connect All Points	C++ • Python • Rust
743	Medium	Network Delay Time	C++ • Python • Rust
778	Hard	Swim in Rising Water	C++ • Python • Rust
269	Hard	Alien Dictionary	C++ • Python • Rust
787	Medium	Cheapest Flights Within K Stops	C++ • Python • Rust

1-D Dynamic Programming

LeetCode ID	Difficulty	Problem	Solution
70	Easy	Climbing Stairs	C++ • Python • Rust
746	Easy	Min Cost Climbing Stairs	C++ • Python • Rust
198	Medium	House Robber	C++ • Python • Rust
213	Medium	House Robber II	C++ • Python • Rust
5	Medium	Longest Palindromic Substring	C++ • Python • Rust
647	Medium	Palindromic Substrings	C++ • Python • Rust
91	Medium	Decode Ways	C++ • Python • Rust
322	Medium	Coin Change	C++ • Python • Rust
152	Medium	Maximum Product Subarray	C++ • Python • Rust
139	Medium	Word Break	C++ • Python • Rust
300	Medium	Longest Increasing Subsequence	C++ • Python • Rust
416	Medium	Partition Equal Subset Sum	C++ • Python • Rust

2-D Dynamic Programing

LeetCode ID	Difficulty	Problem	Solution
62	Medium	Unique Paths	C++ • Python • Rust
1143	Medium	Longest Common Subsequence	C++ • Python • Rust
309	Medium	Best Time to Buy and Sell Stock with Cooldown	C++ • Python • Rust
518	Medium	Coin Change II	C++ • Python • Rust
494	Medium	Target Sum	C++ • Python • Rust
97	Medium	Interleaving String	C++ • Python • Rust
329	Hard	Longest Increasing Path in a Matrix	C++ • Python • Rust
115	Hard	Distinct Subsequences	C++ • Python • Rust
72	Hard	Edit Distance	C++ • Python • Rust
312	Hard	Burst Balloons	C++ • Python • Rust
10	Hard	Regular Expression Matching	C++ • Python • Rust

Greedy

LeetCode ID	Difficulty	Problem	Solution
53	Medium	Maximum Subarray	C++ • Python • Rust
55	Medium	Jump Game	C++ • Python • Rust
45	Medium	Jump Game II	C++ • Python • Rust
134	Medium	Gas Station	C++ • Python • Rust
846	Medium	Hand of Straights	C++ • Python • Rust
1899	Medium	Merge Triplets to Form Target Triplet	C++ • Python • Rust
763	Medium	Partition Labels	C++ • Python • Rust
678	Medium	Valid Parenthesis String	C++ • Python • Rust

Intervals

LeetCode ID	Difficulty	Problem	Solution
57	Medium	Insert Interval	C++ • Python • Rust
56	Medium	Merge Intervals	C++ • Python • Rust
435	Medium	Non-overlapping Intervals	C++ • Python • Rust
252	Easy	Meeting Rooms	C++ • Python • Rust
253	Medium	Meeting Rooms II	C++ • Python • Rust
1851	Hard	Minimum Interval to Include Each Query	C++ • Python • Rust

Math & Geometry

LeetCode ID	Difficulty	Problem	Solution
48	Medium	Rotate Image	C++ • Python • Rust
54	Medium	Spiral Matrix	C++ • Python • Rust
73	Medium	Set Matrix Zeroes	C++ • Python • Rust
202	Easy	Happy Number	C++ • Python • Rust
66	Easy	Plus One	C++ • Python • Rust
50	Medium	Pow(x, n)	C++ • Python • Rust
43	Medium	Multiply Strings	C++ • Python • Rust
2013	Medium	Detect Squares	C++ • Python • Rust

Bit Manipulation

LeetCode ID	Difficulty	Problem	Solution
136	Easy	Single Number	C++ • Python • Rust
191	Easy	Number of 1 Bits	C++ • Python • Rust
338	Easy	Counting Bits	C++ • Python • Rust
190	Easy	Reverse Bits	C++ • Python • Rust
268	Easy	Missing Number	C++ • Python • Rust
371	Medium	Sum of Two Integers	C++ • Python • Rust
7	Medium	Reverse Integer	C++ • Python • Rust

Contributing

If you have a better solution, feel free to open a PR. Add a small summary of your solution with space and time complexities.

Guidelines

• Make sure your code passes all the test cases on LeetCode for the problem it solves.
• Write clean code that is easy to understand.
• Give your PR a succinct and accurate title.