USACO3.21Factorials

枚举

#include <iostream>
/*
    ID: shangca2
    LANG: C++
    TASK: fact4
 */
#include<cstdio>
#include<cstring>
#include<iostream>

using namespace std;
int di[5000];
int main()
{
    freopen("fact4.in","r",stdin);
    freopen("fact4.out","w",stdout);
    int i,j,k,n,g=0;
    di[0] = 1;
    cin>>n;
    for(i = 1 ; i <= n ; i++)
    {
        for(j=0 ; j <= g ; j++)
        di[j] *= i;
        for(j = 0 ; j <= g ; j++)
        {
            if(di[j]>9)
            {
                di[j+1] += di[j]/10;
                di[j] = di[j]%10;
                if(j+1>g)
                g = j+1;
            }
        }
    }
    k=0;
    while(di[k]==0&&k<=g)
    k++;
    cout<<di[k]<<endl;
    return 0;
}