leetcode-----96. 不同的二叉搜索树

• 链接：https://leetcode-cn.com/problems/unique-binary-search-trees/

代码

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