Serialize and Deserialize Binary Tree
Convert a binary tree to a string and rebuild the identical tree from that string.
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Lesson notes
Try it before you watch
Restate the problem in your own words, list the edge cases, and sketch a solution with its running time. Then play the video and compare.
Reveal the key idea
Serialize with a preorder DFS that writes a marker for every missing child; deserialize by reading the tokens back in the same order.
Pattern: Trees & tries. Most tree problems are a recursive question asked of the left subtree, the right subtree, and the root.
Complexity
| Measure | Bound |
|---|---|
| Time | O(n) |
| Extra space | O(n) |
Walkthroughs often start from a simpler approach first; aim to reach these bounds. New to Big-O? Read understanding algorithmic complexity.