Python keeps algorithm practice focused on the problem: compact syntax, useful built-ins, little ceremony.

1. Two Sum: index-pair lookup

2. Add Two Numbers: linked-list arithmetic

3. Longest Substring Without Repeats

4. Median of Two Sorted Arrays

5. Longest Palindromic Substring

6. Zigzag String Conversion

7. Reverse a 32-bit Integer

8. String to Integer (atoi)

9. Palindrome Integer

10. Regular Expression Matching

11. Container With Most Water

12. Integer to Roman

13. Roman to Integer

14. Longest Common Prefix

15. 3Sum

16. 3Sum Closest

17. Phone Number Letter Combinations

18. Count and Say

19. Merge Overlapping Intervals

20. Best Time to Buy and Sell Stock

21. Linked List Cycle

22. Linked List Cycle II