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All topics›JavaScript›Tree problems in depth

Construct Binary Tree from Preorder and Inorder Traversal

advancedlayer I2 · Tree problems in depth5 tests

You are given the preorder traversal and the inorder traversal of the same binary tree, with all values distinct. Rebuild the tree and return its root.

  • Preorder visits node, left, right; inorder visits left, node, right
  • Together the two orders pin down exactly one tree
  • Two empty arrays produce null
  • Use toArray(root) to inspect what you built

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