(LEETCODE) Unique Binary Search Trees.cpp

class Solution {
public:   
    
    int numTrees(int n){
        int dp[n+1];
        dp[0]=dp[1]=1;
        for (int i = 2; i <= n; i++) {
        dp[i] = 0;
        for (int j = 0; j < i; j++)
            dp[i] += dp[j] * dp[i - j - 1];
    }
 
        return dp[n];
    }
};