题解 | #n的阶乘#

用递推比递归更加快

#include <iostream>
using namespace std;

typedef long long LL;
LL fact[25];

int main()
{
    int n;
    cin >> n;
    fact[0] = 1;
    for (int i = 1; i <= n; ++i)
        fact[i] = i * fact[i-1];
    cout << fact[n] << endl;
}