leetcode

0 class Solution {

1 public:

2 int numTrees(int n) {

3 vector<int> dp(n + 1);

4 dp[0] = dp[1] = 1;

5

6 for (int i = 2; i <= n; i++)

7 for (int j = 1; j <= i; j++)

8 dp[i] += dp[j - 1] * dp[i - j];

9 return dp.back();

10 }

11 };