题解 | #有多少个不同的二叉搜索树#

#include <cstring>
#include <iostream>
using namespace std;

int main() {
    int n;
    cin >> n;
    int f[n + 1];
    memset(f, 0, sizeof f);
    f[1] = f[0] = 1;
    for(int i = 2; i <= n; i ++){
        for(int j = 1; j <= i; j ++){
            f[i] += f[j - 1] * f[i - j];
        }
    }
    cout << f[n] << endl;
}