AlgoSolveoRoadmap › Stage 7: Heaps & Backtracking › Pattern 34 of 53
DSA pattern guide
Backtracking — Constraint Based
Puzzles and grids: N-Queens, Sudoku, word search.
Use it when
Puzzles and grids: N-Queens, Sudoku, word search.
Key idea
Place, check constraints early, recurse, undo. Prune as soon as a state can't lead to an answer.
Practice problems, in order
- Partition to K Equal Sum SubsetsMedium
- Word SearchMedium
- Path with Maximum GoldMedium
- N-QueensHard
- Sudoku SolverHard
- Word Search IIHard
- Unique Paths IIIHard
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?
The AlgoSolveo extension (free, launching soon) sits beside the LeetCode problem and gives the smallest hint that gets you moving, never the full answer. Solved problems tick off on your roadmap.
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