class Solution {public:    TreeNode *buildTree(vector<int>& inorder, int in_left,int in_right,                        vector<int>& postorder,  int post_left, int post_right){        if(in_right < in_left || post_right < post_left) return NULL;        TreeNode *root = new TreeNode(postorder[post_right]);        int index = in_left;        for( ; index <= in_right; ++ index ) if(inorder[index] == postorder[post_right])  break;        int right_cnt = in_right-index;        root->left = buildTree(inorder,in_left,index-1,postorder,post_left,post_right-right_cnt-1);        root->right = buildTree(inorder,index+1,in_right,postorder, post_right-right_cnt,post_right-1);        return root;    }    TreeNode *buildTree(vector<int> &inorder, vector<int> &postorder) {        if(inorder.size() == 0) return NULL;        else return buildTree(inorder,0,inorder.size()-1, postorder,0,postorder.size()-1);    }};