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.

class Solution {
public:
    TreeNode *buildTree(vector<int> &inorder, vector<int> &postorder) {
        return build_Tree(inorder.begin(), inorder.end(), postorder.begin(), postorder.end());
    }
    
    TreeNode *build_Tree(vector<int>::iterator in_b, vector<int>::iterator in_e, vector<int>::iterator post_b, vector<int>::iterator post_e){
        if(in_b == in_e || post_b == post_e) return NULL;
        
        TreeNode *root = new TreeNode(*prev(post_e));
        auto root_p = find(in_b, in_e, *prev(post_e));
        auto tmp = next(post_b, distance(in_b, root_p));
        
        root->left = build_Tree(in_b, root_p, post_b, tmp);
        root->right = build_Tree(next(root_p), in_e, tmp, prev(post_e));
        
        return root;
    }
};