Solution: Recover a Tree From Preorder Traversal
Understand how to recover the original binary tree by parsing its preorder traversal string that encodes node depths with dashes. Explore the DFS strategy to build the tree recursively by interpreting depth levels and node values. This lesson helps you apply a single-pass approach with efficient time and space complexity to solve tree reconstruction problems.
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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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