Construct Binary Tree

pre-order + in-order

Given preorder and inorder traversal of a tree, construct the binary tree.

Note: You may assume that duplicates do not exist in the tree.

For example, given

preorder = [3,9,20,15,7] inorder = [9,3,15,20,7]

Return the following binary tree:

    3
   / \
  9  20
    /  \
   15   7

思路和解法

post order + in-order

Given inorder and postorder traversal of a tree, construct the binary tree.

Note: You may assume that duplicates do not exist in the tree.

For example, given

inorder = [9,3,15,20,7] postorder = [9,15,7,20,3] Return the following binary tree:


    3
   / \
  9  20
    /  \
   15   7