AlgoSolveoRoadmap › Stage 9: Greedy & Dynamic Programming › Pattern 49 of 53
DSA pattern guide
DP — Trees & DAGs
Optimal choices on trees (rob or skip a node).
Use it when
Optimal choices on trees (rob or skip a node).
Key idea
Post-order DFS returns a small tuple per node, such as (take, skip).
Practice problems, in order
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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