package main import . "nc_tools" //递归,时空On func reConstructBinaryTree( pre []int , vin []int ) *TreeNode { if len(pre) == 0 { return nil } root := &TreeNode{pre[0], nil, nil} i := 0 for i = 0; i < len(vin); i++ { if vin[i] == pre[0] { break } } root.Left = reConstructBinaryTree(pre[1: len(vin[: i]) +1], vin[: i]) root.Right = reConstructBinaryTree(pre[len(vin[: i]) +1: ], vin[i +1:]) return root }