Hash Map Patterns
Problems using hash map techniques
33 lessons
88 min
Lessons
1. What is Hash Map Patterns
Pattern overview
2m
2. Prerequisites
What you need first
1m
3. When to Use
Pattern triggers
2m
4. When NOT to Use
Avoid forcing this pattern
2m
5. Hash vs Array: When to Use Which
Choosing the right structure
2m
6. LeetCode 1 Two Sum - Problem Statement
The problem
2m1 problems
7. Quiz: What Makes a Good Hash Map Key
Test your understanding
2m1 problems
8. LeetCode 1 Two Sum - Solution
The core idea
3m
9. LeetCode 1 Two Sum - Example and Complexity Analysis
Walkthrough and analysis
3m
10. LeetCode 1 Two Sum - Implementation
The approach
4m1 problems
11. LeetCode 49 Group Anagrams - Problem Statement
The problem
2m1 problems
12. LeetCode 49 Group Anagrams - Why Naive Fails
The trap
2m
13. LeetCode 49 Group Anagrams - Solution
The core idea
3m
14. LeetCode 49 Group Anagrams - Example and Complexity Analysis
Walkthrough and analysis
3m
15. LeetCode 49 Group Anagrams - Implementation
The approach
4m1 problems
16. LeetCode 128 Longest Consecutive Sequence - Problem Statement
The problem
2m1 problems
17. Quiz: Identifying Sequence Starts
Test your understanding
2m1 problems
18. LeetCode 128 Longest Consecutive Sequence - Why Naive Fails
The trap
2m
19. LeetCode 128 Longest Consecutive Sequence - Solution
The core idea
3m
20. LeetCode 128 Longest Consecutive Sequence - Example and Complexity Analysis
Walkthrough and analysis
3m
21. LeetCode 128 Longest Consecutive Sequence - Implementation
The approach
4m1 problems
22. LeetCode 347 Top K Frequent Elements - Problem Statement
The problem
2m1 problems
23. LeetCode 347 Top K Frequent Elements - Why Naive Fails
The trap
2m
24. LeetCode 347 Top K Frequent Elements - Solution
The core idea
3m
25. LeetCode 347 Top K Frequent Elements - Example and Complexity Analysis
Walkthrough and analysis
3m
26. LeetCode 347 Top K Frequent Elements - Implementation
The approach
4m1 problems
27. LeetCode 149 Max Points on Line - Problem Statement
The problem
3m1 problems
28. LeetCode 149 Max Points on Line - Why Naive Fails
Why brute force fails
3m
29. LeetCode 149 Max Points on Line - Solution
The pattern
4m
30. LeetCode 149 Max Points on Line - Example and Complexity Analysis
Walkthrough and analysis
3m
31. LeetCode 149 Max Points on Line - Implementation
The code
5m1 problems
32. Common Mistakes
Common errors to avoid
2m
33. Section Recap
Summary
1m
Practice Problems
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
12.
13.
14.
15.
16.
17.
18.
19.