---

1. Generate all binary strings
2. Generate Parenthesis
3. Print all subsequences / Power Set
4. Learn All Patterns of Subsequences (Theory)
5. Count all subsequences with sum K
6. Check if there exists a subsequence with sum K
7. Combination Sum
8. Combination Sum II
9. Subset Sum I
10. Subset Sum II
11. Combination Sum III
12. Letter Combinations of a Phone Number