LeetCode: Construct Binary Tree from Preorder and Postorder Traversal

// https://code.dennyzhang.com/construct-binary-tree-from-preorder-and-postorder-traversal
// Basic Ideas:
// Complexity: Time ?, Space O?
/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */
func constructFromPrePost(pre []int, post []int) *TreeNode {
    if len(pre) == 0 { return nil }
    res := &TreeNode{pre[0], nil, nil}
    if len(pre) == 1 { return res }
    for i:=len(pre)-1; i>=0; i-- {
        if post[i] == pre[1] {
            res.Left = constructFromPrePost(pre[1:i+2], post[0:i+1])
            res.Right = constructFromPrePost(pre[i+2:], post[i+1:len(pre)-1])
            break
        }
    }
    return res
}