25 DP Problems To Revise Before Interviews
I've posted many complete resource guides recently - covering patterns, variations, and tons of problems for each topic. They're great for learning from scratch or extensive practice, but if your interview is already scheduled, covering 50-70 problems per topic just isn't realistic.
That's why I'm creating focused problem lists for each topic, just 10-25 essential problems that cover the complete breadth of what you need.
Starting today with DP: 25 carefully selected problems covering every major DP pattern for interviews. If you're interviewing at Google or other DSA-heavy companies, you might need extra practice, but for most tech interviews, this list is a solid foundation.
The 25 Essential Problems
1. Climbing Stairs - LeetCode 70
- Pattern: Basic DP, Fibonacci recurrence
- Why: Foundation of all DP, teaches recursion → memoization → tabulation
2. House Robber - LeetCode 198
- Pattern: Include/Exclude decision
- Why: Classic choice pattern, appears in many forms
3. House Robber II - LeetCode 213
- Pattern: Circular array
- Why: Teaches constraint handling
4. Decode Ways - LeetCode 91
- Pattern: Count ways
- Why: Common in interviews, multiple transitions
5. Jump Game II - LeetCode 45
- Pattern: Minimum steps
- Why: Optimization + greedy thinking
6. Unique Paths - LeetCode 62
- Pattern: Basic 2D DP
- Why: Foundation for all grid problems
7. Minimum Path Sum - LeetCode 64
- Pattern: Cost optimization on grid
- Why: Very common in interviews
8. Longest Common Subsequence - LeetCode 1143
- Pattern: LCS (2D string DP)
- Why: Foundation for all string comparison
9. Edit Distance - LeetCode 72
- Pattern: String transformation
- Why: Frequently asked, shows operations clearly
10. Partition Equal Subset Sum - LeetCode 416
- Pattern: 0/1 Knapsack (subset sum)
- Why: Foundation of knapsack, must know
11. Target Sum - LeetCode 494
- Pattern: Count ways knapsack
- Why: Shows knapsack in disguise
12. Coin Change - LeetCode 322
- Pattern: Unbounded knapsack (minimize)
- Why: Classic, very frequently asked
13. Coin Change II - LeetCode 518
- Pattern: Unbounded knapsack (count ways)
- Why: Complements Coin Change, different objective
14. Ones and Zeroes - LeetCode 474
- Pattern: 2D knapsack
- Why: Multiple constraints variation
15. Longest Increasing Subsequence - LeetCode 300
- Pattern: LIS (know both O(n²) and O(n log n))
- Why: Must-know, appears in many variations
16. Longest Palindromic Substring - LeetCode 5
- Pattern: Palindrome problems
- Why: Classic problem, multiple approaches
17. Palindromic Substrings - LeetCode 647
- Pattern: Count palindromes
- Why: Counting variant, builds on problem 16
18. Word Break - LeetCode 139
- Pattern: String partition
- Why: Common pattern, dictionary-based DP
19. Best Time to Buy and Sell Stock - LeetCode 121
- Pattern: One transaction
- Why: Foundation, simple but important
20. Best Time to Buy and Sell Stock II - LeetCode 122
- Pattern: Unlimited transactions
- Why: Introduces state concept
21. Best Time to Buy and Sell Stock with Cooldown - LeetCode 309
- Pattern: State machine
- Why: Teaches state transitions clearly
22. Best Time to Buy and Sell Stock IV - LeetCode 188
- Pattern: K transactions (generalizes all stocks)
- Why: Master this, master all stock problems
23. Unique Paths II - LeetCode 63
- Pattern: Grid with obstacles
- Why: Adds constraints to grid DP
24. Triangle - LeetCode 120
- Pattern: Non-rectangular grid
- Why: Variable width DP
25. Palindrome Partitioning II - LeetCode 132
- Pattern: Partition DP
- Why: Advanced string DP, commonly asked
Final Advice
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Quality over quantity. 25 deeply understood problems > 100 half-understood problems.
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Focus on patterns. When you solve problem 10 (Partition Equal Subset Sum), you're not learning one problem. You're learning the subset sum pattern that appears in dozens of problems.
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Code, don't read. Reading solutions feels productive but doesn't work. You need to actually code these.
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Time yourself. In interviews, you'll have 30-40 minutes. Practice under time pressure.
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Revise. Solve each problem twice - once now, once 3 days later.
Related Posts
Check out my posts which may help you in your preparation :
- Complete DP Problems & Resources Guide
- Complete Graph Problems & Resources Guide
- 13 DP Patterns for Interview Preparation
- 10 Dijkstra Variations for Interview Preparation
- Understanding Time Complexity: The 10^8 Operations Rule
- 10 Essential Design Problems for DSA Interviews
- Essential CS Fundamental Topics For Interviews
- Essential Graph Patterns for Coding Interviews
- Essential String Patterns for Coding Interviews
- 15 Essential DSA Patterns for Tech Interviews
- The 10 Variations of Two Pointers for Interview Preparation
These 25 problems are your DP foundation. Master them, and DP becomes one of your strengths instead of a weakness.
Now stop reading. Open problem 1. Start coding.
Good luck! 🚀