[LeetCode] 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.

/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    TreeNode *buildTree(vector<int> &inorder, vector<int> &postorder) {
        if (inorder.empty() || postorder.empty())
            return NULL;
            return buildTree(inorder.begin(), inorder.end() - 1, postorder.begin(), postorder.end() - 1);
        }
    template<typename Iter>
    TreeNode* buildTree(Iter inBegin, Iter inEnd, Iter postBegin, Iter postEnd) {
        if (inBegin > inEnd) return nullptr;
        if (postBegin > postEnd) return nullptr;
        
        TreeNode *root = new TreeNode(*postEnd);
        Iter in_root_pos = find(inBegin, inEnd, *postEnd);
        int left_length = in_root_pos - inBegin;
        root->left = buildTree(inBegin, in_root_pos - 1, postBegin, postBegin + left_length - 1);
        root->right = buildTree(in_root_pos + 1, inEnd, postBegin + left_length, postEnd - 1);
        
        return root;
    }
};