LeetCode Questions for Interview

This repository contains categorized lists of LeetCode questions commonly asked in technical interviews. It is curated to help you strengthen your understanding of essential Data Structures and Algorithms by topic.

Each section includes direct problem links. You can use this list for tracking, structured revision, or daily practice.

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Categories Covered

• Arrays & Strings
• Linked Lists
• Trees & Binary Search Trees (BST)
• Graphs
• Dynamic Programming
• Backtracking
• Heaps & Priority Queues
• Sorting & Searching
• Stacks & Queues
• Hashing

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Problem List

#	Problem Name	Link
1	Two Sum	https://leetcode.com/problems/two-sum/
2	Best Time to Buy and Sell Stock	https://leetcode.com/problems/best-time-to-buy-and-sell-stock/
3	Maximum Subarray	https://leetcode.com/problems/maximum-subarray/
4	Product of Array Except Self	https://leetcode.com/problems/product-of-array-except-self/
5	Valid Anagram	https://leetcode.com/problems/valid-anagram/
6	Combination Sum II	https://leetcode.com/problems/combination-sum-ii/
7	Group Anagrams	https://leetcode.com/problems/group-anagrams/description/
8	Longest Substring Without Repeating Characters	https://leetcode.com/problems/longest-substring-without-repeating-characters/description/
9	Minimum Window Substring	https://leetcode.com/problems/minimum-window-substring/description/
10	Longest Palindromic Substring	https://leetcode.com/problems/longest-palindromic-substring/description/
11	Coin Change	https://leetcode.com/problems/coin-change/description/
12	Combination Sum	https://leetcode.com/problems/combination-sum/description/

Linked Lists

#	Problem Name	Link
1	Reverse Linked List	https://leetcode.com/problems/reverse-linked-list/description/
2	Linked List Cycle	https://leetcode.com/problems/linked-list-cycle/description/
3	Intersection of Two Linked Lists	https://leetcode.com/problems/intersection-of-two-linked-lists/description/
4	Remove Nth Node From End	https://leetcode.com/problems/remove-nth-node-from-end-of-list/description/
5	Palindrome Linked List, Add Two Numbers	https://www.geeksforgeeks.org/sum-of-all-palindrome-numbers-present-in-a-linked-list/

Trees & BST

#	Problem Name	Link
1	Maximum Depth of Binary Tree	https://leetcode.com/problems/maximum-depth-of-binary-tree/description/
2	Invert Binary Tree	https://leetcode.com/problems/invert-binary-tree/description/
3	Binary Tree Level Order Traversal	https://leetcode.com/problems/binary-tree-level-order-traversal/description/
4	Symmetric Tree	https://leetcode.com/problems/symmetric-tree/description/
5	Validate BST	https://leetcode.com/problems/validate-binary-search-tree/description/
6	Lowest Common Ancestor of BST	https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree/description/
7	Construct a Binary Tree from Preorder and Inorder	https://www.geeksforgeeks.org/dsa/construct-tree-from-given-inorder-and-preorder-traversal/

Graphs

#	Problem Name	Link
1	Number of Islands	https://leetcode.com/problems/number-of-islands/description/
2	Clone Graph	https://leetcode.com/problems/clone-graph/description/
3	Course Schedule	https://leetcode.com/problems/course-schedule/description/
4	Word Search	https://leetcode.com/problems/word-search/description/

Dynamic Programming

#	Problem Name	Link
1	House Robber	https://leetcode.com/problems/house-robber/
2	Decode Ways	https://leetcode.com/problems/decode-ways/description/
3	Unique Paths	https://leetcode.com/problems/unique-paths/description/
4	Jump Game	https://leetcode.com/problems/jump-game/description/
5	Longest Increasing Subsequence	https://leetcode.com/problems/longest-increasing-subsequence/description/
6	Word Break	https://leetcode.com/problems/word-break/description/

Backtracking

#	Problem Name	Link
1	Subsets	https://leetcode.com/problems/subsets/description/
2	Combination Sum	https://leetcode.com/problems/combination-sum/description/
3	Word Search	https://leetcode.com/problems/word-search/description/

Heaps & Priority Queues

#	Problem Name	Link
1	Kth Largest Element in Array	https://leetcode.com/problems/kth-largest-element-in-an-array/
2	LRU Cache	https://leetcode.com/problems/lru-cache/description/
3	Min Stack	https://leetcode.com/problems/min-stack/description/

Sorting & Searching

#	Problem Name	Link
1	Merge Intervals	https://leetcode.com/problems/merge-intervals/
2	Find Minimum in Rotated Sorted Array	https://leetcode.com/problems/find-minimum-in-rotated-sorted-array/description/
3	Search in Rotated Sorted Array	https://leetcode.com/problems/search-in-rotated-sorted-array/description/
4	Merge Two Sorted Lists	https://leetcode.com/problems/merge-two-sorted-lists/description/

Stacks & Queues

#	Problem Name	Link
1	Valid Parentheses	https://leetcode.com/problems/valid-parentheses/description/
2	Sliding Window Maximum	https://leetcode.com/problems/sliding-window-maximum/description/
3	Stock Span Problem	https://leetcode.com/problems/online-stock-span/description/

Hashing

#	Problem Name	Link
1	Valid Anagram	https://leetcode.com/problems/valid-anagram/description/
2	Group Anagrams	https://leetcode.com/problems/group-anagrams/description/
3	Longest Substring Without Repeating Characters	https://leetcode.com/problems/longest-substring-without-repeating-characters/description/

How to Use This Repository

• Visit each link and solve the problems directly on LeetCode or GeeksforGeeks.
• Maintain a Google Sheet or markdown log to track:
  • Status (Solved / Revisit / Not Attempted)
  • Date Solved
  • Notes / Edge Cases
  • Key Concepts
• Optionally, create a solutions/ directory in this repo to store your code solutions in Python, C++, or any preferred language.

Goal

To develop strong problem-solving skills, recognize patterns, and prepare thoroughly for coding interviews through structured topic-wise practice.

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Note: This list is part of my personal preparation. Feel free to fork and adapt it for your own interview journey.