Solution: Recover a Tree From Preorder Traversal
Explore how to rebuild a binary tree from a preorder traversal string encoded with depth dashes. Understand applying depth-first search to parse node depth and value, recursively constructing left and right children in the correct order. This lesson teaches an efficient single-pass algorithm for tree recovery useful in coding interviews.
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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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