# 🔥 Stop Solving Random Problems — Master These 75 Questions First

Most candidates jump from one problem to another without a clear roadmap.

If you're preparing for coding interviews, these 75 questions cover the most important patterns asked by top tech companies.

Topics covered:
✅ Arrays  
✅ Strings  
✅ Linked Lists  
✅ Trees  
✅ Graphs  
✅ Dynamic Programming  
✅ Intervals  
✅ Heaps  
✅ Binary Operations  

Master these before moving on to random problems.

Happy Coding! 🚀

---

# Array

- [Two Sum](https://leetcode.com/problems/two-sum/)
- [Best Time to Buy and Sell Stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock/)
- [Contains Duplicate](https://leetcode.com/problems/contains-duplicate/)
- [Product of Array Except Self](https://leetcode.com/problems/product-of-array-except-self/)
- [Maximum Subarray](https://leetcode.com/problems/maximum-subarray/)
- [Maximum Product Subarray](https://leetcode.com/problems/maximum-product-subarray/)
- [Find Minimum in Rotated Sorted Array](https://leetcode.com/problems/find-minimum-in-rotated-sorted-array/)
- [Search in Rotated Sorted Array](https://leetcode.com/problems/search-in-rotated-sorted-array/)
- [3 Sum](https://leetcode.com/problems/3sum/)
- [Container With Most Water](https://leetcode.com/problems/container-with-most-water/)

---

# Binary

- [Sum of Two Integers](https://leetcode.com/problems/sum-of-two-integers/)
- [Number of 1 Bits](https://leetcode.com/problems/number-of-1-bits/)
- [Counting Bits](https://leetcode.com/problems/counting-bits/)
- [Missing Number](https://leetcode.com/problems/missing-number/)
- [Reverse Bits](https://leetcode.com/problems/reverse-bits/)

---

# Dynamic Programming

- [Climbing Stairs](https://leetcode.com/problems/climbing-stairs/)
- [Coin Change](https://leetcode.com/problems/coin-change/)
- [Longest Increasing Subsequence](https://leetcode.com/problems/longest-increasing-subsequence/)
- [Longest Common Subsequence](https://leetcode.com/problems/longest-common-subsequence/)
- [Word Break](https://leetcode.com/problems/word-break/)
- [Combination Sum IV](https://leetcode.com/problems/combination-sum-iv/)
- [House Robber](https://leetcode.com/problems/house-robber/)
- [House Robber II](https://leetcode.com/problems/house-robber-ii/)
- [Decode Ways](https://leetcode.com/problems/decode-ways/)
- [Unique Paths](https://leetcode.com/problems/unique-paths/)
- [Jump Game](https://leetcode.com/problems/jump-game/)

---

# Graph

- [Clone Graph](https://leetcode.com/problems/clone-graph/)
- [Course Schedule](https://leetcode.com/problems/course-schedule/)
- [Pacific Atlantic Water Flow](https://leetcode.com/problems/pacific-atlantic-water-flow/)
- [Number of Islands](https://leetcode.com/problems/number-of-islands/)
- [Longest Consecutive Sequence](https://leetcode.com/problems/longest-consecutive-sequence/)
- [Alien Dictionary](https://leetcode.com/problems/alien-dictionary/)
- [Graph Valid Tree](https://leetcode.com/problems/graph-valid-tree/)
- [Number of Connected Components in an Undirected Graph](https://leetcode.com/problems/number-of-connected-components-in-an-undirected-graph/)

---

# Interval

- [Insert Interval](https://leetcode.com/problems/insert-interval/)
- [Merge Intervals](https://leetcode.com/problems/merge-intervals/)
- [Non-overlapping Intervals](https://leetcode.com/problems/non-overlapping-intervals/)
- [Meeting Rooms](https://leetcode.com/problems/meeting-rooms/)
- [Meeting Rooms II](https://leetcode.com/problems/meeting-rooms-ii/)

---

# Linked List

- [Reverse Linked List](https://leetcode.com/problems/reverse-linked-list/)
- [Linked List Cycle](https://leetcode.com/problems/linked-list-cycle/)
- [Merge Two Sorted Lists](https://leetcode.com/problems/merge-two-sorted-lists/)
- [Merge K Sorted Lists](https://leetcode.com/problems/merge-k-sorted-lists/)
- [Remove Nth Node From End of List](https://leetcode.com/problems/remove-nth-node-from-end-of-list/)
- [Reorder List](https://leetcode.com/problems/reorder-list/)

---

# Matrix

- [Set Matrix Zeroes](https://leetcode.com/problems/set-matrix-zeroes/)
- [Spiral Matrix](https://leetcode.com/problems/spiral-matrix/)
- [Rotate Image](https://leetcode.com/problems/rotate-image/)
- [Word Search](https://leetcode.com/problems/word-search/)

---

# String

- [Longest Substring Without Repeating Characters](https://leetcode.com/problems/longest-substring-without-repeating-characters/)
- [Longest Repeating Character Replacement](https://leetcode.com/problems/longest-repeating-character-replacement/)
- [Minimum Window Substring](https://leetcode.com/problems/minimum-window-substring/)
- [Valid Anagram](https://leetcode.com/problems/valid-anagram/)
- [Group Anagrams](https://leetcode.com/problems/group-anagrams/)
- [Valid Parentheses](https://leetcode.com/problems/valid-parentheses/)
- [Valid Palindrome](https://leetcode.com/problems/valid-palindrome/)
- [Longest Palindromic Substring](https://leetcode.com/problems/longest-palindromic-substring/)
- [Palindromic Substrings](https://leetcode.com/problems/palindromic-substrings/)
- [Encode and Decode Strings](https://leetcode.com/problems/encode-and-decode-strings/)

---

# Tree

- [Maximum Depth of Binary Tree](https://leetcode.com/problems/maximum-depth-of-binary-tree/)
- [Same Tree](https://leetcode.com/problems/same-tree/)
- [Invert Binary Tree](https://leetcode.com/problems/invert-binary-tree/)
- [Binary Tree Maximum Path Sum](https://leetcode.com/problems/binary-tree-maximum-path-sum/)
- [Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal/)
- [Serialize and Deserialize Binary Tree](https://leetcode.com/problems/serialize-and-deserialize-binary-tree/)
- [Subtree of Another Tree](https://leetcode.com/problems/subtree-of-another-tree/)
- [Construct Binary Tree from Preorder and Inorder Traversal](https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/)
- [Validate Binary Search Tree](https://leetcode.com/problems/validate-binary-search-tree/)
- [Kth Smallest Element in a BST](https://leetcode.com/problems/kth-smallest-element-in-a-bst/)
- [Lowest Common Ancestor of a BST](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree/)
- [Implement Trie (Prefix Tree)](https://leetcode.com/problems/implement-trie-prefix-tree/)
- [Add and Search Word](https://leetcode.com/problems/add-and-search-word-data-structure-design/)
- [Word Search II](https://leetcode.com/problems/word-search-ii/)

---

# Heap

- [Merge K Sorted Lists](https://leetcode.com/problems/merge-k-sorted-lists/)
- [Top K Frequent Elements](https://leetcode.com/problems/top-k-frequent-elements/)
- [Find Median from Data Stream](https://leetcode.com/problems/find-median-from-data-stream/)

---

# Bonus Resources

- [14 Patterns to Ace Any Coding Interview Question](https://hackernoon.com/14-patterns-to-ace-any-coding-interview-question-c5bb3357f6ed)
- [Grind 75](https://www.techinterviewhandbook.org/grind75)

---

**⭐ Save this post for future revision.**

*💬 How many of these 75 have you completed?*

<p >
  <img src="https://assets.leetcode.com/users/images/c684e8a6-83c3-4471-9e11-4530835657f6_1781879870.1038055.png" width="250">
</p>

**CHECK OUT :** [🎯 DP & Graphs: The Only LeetCode List Most Interview Candidates & FAANG Aspirants Need](https://leetcode.com/discuss/post/8345243/dp-graphs-the-only-leetcode-list-most-in-lcil/)



🔥 Stop Solving Random Problems — Master These 75 Questions FirstMost candidates jump from one problem to another without a clear roadmap.If you're preparing for coding interviews, these 75 questions cover the most important patterns asked by top tech