Welcome to the Leetcode 250 repository – a curated collection of the 250 most frequently asked Leetcode questions with clean Python solutions, detailed explanations, and optimized code — ideal for preparing for FAANG, Big Tech, and startup coding interviews.
✅ If you’re searching for:
Leetcode 250·Top 250 Leetcode Problems·FAANG Coding Prep·Python Interview Questions
Most Asked Leetcode Questions·Leetcode DSA Sheet·Leetcode for Big Tech Interviews
Data Structures and Algorithms in Python·Top Leetcode List 2024·Best Leetcode Questions to Practice
Leetcode Pattern-Based Practice·Python Coding Interview Guide·Google Amazon Meta Interview Leetcode
Top DSA Problems for Product Based Companies·Coding Round Preparation in Python
Neetcode 150 vs Leetcode 250·Leetcode Python Tracker·Crack the Coding Interview with LeetcodeYou’ve landed in the right place.
✔️ 250 curated questions to maximize your DSA preparation
✔️ Clean and readable Python solutions
✔️ Includes intuition, approach, time/space complexity
✔️ Structured by topic for ease of learning
✔️ Suitable for Google, Amazon, Meta, Microsoft, Netflix
✔️ Regular updates and daily commit logs
✔️ Easy folder navigation and problem search
| 💡 Topic | 📌 Folder Name | 📊 Problem Count |
|---|---|---|
| Arrays & Strings | arrays_strings/ |
~40 problems |
| Linked Lists | linked_lists/ |
~20 problems |
| Trees & Binary Trees | trees/ |
~35 problems |
| Graphs & Traversals | graphs/ |
~25 problems |
| Dynamic Programming | dp/ |
~40 problems |
| Sliding Window | sliding_window/ |
~20 problems |
| Binary Search | binary_search/ |
~15 problems |
| Backtracking | backtracking/ |
~20 problems |
| Stack & Queues | stack_queue/ |
~15 problems |
| Heap & Greedy | heap_greedy/ |
~15 problems |
| Bit Manipulation | bit_manipulation/ |
~10 problems |
| Math & Logic | math_logic/ |
~10 problems |
| Others & Miscellaneous | others/ |
~5 problems |
📖 Detailed topic guide: See TOPICS.md for comprehensive explanations of each category.
📊 Progress Tracker
✅ Total Questions: 250
🔄 Solved: XX
📅 Updates: Daily commits
🎯 Track your progress: Run
python progress_tracker.pyto monitor your completion status across all categories.
⭐ Stars, forks, and contributions are welcome!
⭐ Support & Share
If this project helps you:
🌟 Give it a star
🍴 Fork it to your profile
🗣️ Share with friends and aspiring interview candidates
"""
Problem: 121. Best Time to Buy and Sell Stock
Link: https://leetcode.com/problems/best-time-to-buy-and-sell-stock/
Level: Easy
Approach:
- Track the minimum price seen so far
- Track the maximum profit if sold today
Time Complexity: O(n)
Space Complexity: O(1)
"""
def maxProfit(prices):
min_price = float('inf')
max_profit = 0
for p in prices:
min_price = min(min_price, p)
max_profit = max(max_profit, p - min_price)
return max_profit