AlgoSolveoRoadmap › Stage 7: Heaps & Backtracking › Pattern 33 of 53
DSA pattern guide
Backtracking — Choice Based
All subsets, combinations, permutations, partitions.
Use it when
All subsets, combinations, permutations, partitions.
Key idea
Choose, recurse, un-choose. Sort first and skip equal neighbours to avoid duplicates.
Practice problems, in order
- SubsetsMedium
- Subsets IIMedium
- Combination SumMedium
- Combination Sum IIMedium
- PermutationsMedium
- Permutations IIMedium
- Generate ParenthesesMedium
- Palindrome PartitioningMedium
- Restore IP AddressesMedium
How to practise this pattern
- Read the problem and look for the signal above before writing any code.
- Say the brute force out loud, with its time complexity, then ask what work it repeats.
- Apply the key idea and write the optimised version yourself.
- If you're stuck for more than 10 minutes, take one small hint, not the full solution.
- Move to the next problem only when you can explain why this pattern fits.
Stuck on one of these?
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