Construct Binary Tree from Inorder and Postorder Traversal

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

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

#include<iostream>#include<vector>#include<algorithm>using namespace std;struct TreeNode {int val;TreeNode *left;TreeNode *right;TreeNode(int x) : val(x), left(NULL), right(NULL) {}};TreeNode *CreatTree(vector<int>::iterator in_begin, vector<int>::iterator in_end, vector<int>::iterator pos_begin, vector<int>::iterator pos_end ){if (in_begin == in_end)return NULL;vector<int>::iterator Rootpos = pos_end-1;vector<int>::iterator Rootino = find(in_begin, in_end, *Rootpos);auto lenleft = distance(in_begin, Rootino);TreeNode *root = new TreeNode(*Rootpos);root->left  = CreatTree(in_begin, Rootino, pos_begin, pos_begin + lenleft);root->right = CreatTree(Rootino + 1, in_end, pos_begin + lenleft, Rootpos);return root;}TreeNode *buildTree(vector<int> &inorder, vector<int> &postorder) {if (inorder.empty())return NULL;TreeNode *Root = new TreeNode(0);Root = CreatTree(inorder.begin(), inorder.end(), postorder.begin(), postorder.end());return Root;}