94. Construct Binary Tree from Preorder and Inorder Traversal

MediumTree

Given two integer arrays preorder and inorder where preorder is the preorder traversal of a binary tree and inorder is the inorder traversal of the same tree, construct and return the binary tree.

Examples

Input: [3,9,20,15,7] [9,3,15,20,7]

Output: [3,9,20,null,null,15,7]

Explanation: Preorder root 3 splits inorder into left [9] and right [15,20,7].

Constraints

  • 1 <= preorder.length <= 3000
  • inorder.length == preorder.length
  • -3000 <= preorder[i], inorder[i] <= 3000
  • preorder and inorder consist of unique values.
  • Each value of inorder also appears in preorder.
  • preorder is guaranteed to be the preorder traversal of the tree.
  • inorder is guaranteed to be the inorder traversal of the tree.
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