/**
knakul853
 */
class Solution {
public:
    TreeNode* buildTree(vector<int>& preorder, vector<int>& inorder)
    {
        int n = (int)preorder.size();
        int m = (int)preorder.size();

       return dfs(preorder, 0, n-1, inorder, 0, m-1 );
    }

    TreeNode* dfs( vector<int>&pre, int pl,int pr, vector<int>&in, int il, int ir )
    {
        if( pl > pl || il > ir )
            return NULL;
        TreeNode* root = new TreeNode(pre[pl]);

        int id = -1;
        for(int i=il; i<=ir; i++)
        {
            if(in[i] == pre[pl])
            {
                id = i;
                break;
            }
        }

        if(id != -1)
        {

          root->left = dfs(pre, pl + 1, pr, in, il, id-1);

          root->right = dfs(pre, pl + id - il + 1, pr, in,  id + 1, ir);

        }

        return root;

    }
};