Path Problems
Property problems ask each child a question and wait for the answer to climb back up. Path problems run the other way: you hand every child the running total so far and check it once you reach a leaf. That one reversal decides the whole shape of the code, so once you internalize it these problems stop feeling like separate puzzles.
The Pattern: Path problems pass a running state DOWN the tree as you recurse. When you hit a leaf, you check or record the accumulated state.
Unlike tree properties (bottom-up/postorder), path problems flow top-down/preorder.
Unlike tree properties (bottom-up/postorder), path problems flow top-down/preorder.
What's inside
- 1 problem, worked step by step
- about 25 min
Premium lessonData Structures & Algorithms
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