Solution: Recover a Tree From Preorder Traversal
Explore how to recover a binary tree from a preorder traversal string by implementing a depth-first search that uses dash counts to determine node depth. This lesson teaches you to parse the traversal, build nodes recursively, and handle tree reconstruction efficiently with O(n) time complexity and O(h) space complexity.
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Statement
We perform a preorder depth-first traversal on a binary tree starting from its root.
For each node, we first write D dashes, where D is the depth of the node in the tree, followed by the node’s integer value.
The root node has depth 0.
If a node is at depth D, its children (if any) will appear at depth D + 1.
If a node has only one child, it will always be the left child.
You are given the string representation of this traversal. Your task is to reconstruct the original binary tree and return its root.
Constraints:
The number of nodes in the original binary tree lies within the range
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