51nod 1057 N的阶乘 (大数运算)

 1 #include <cstdio>
 2 #include <string>
 3 #include <cstring>
 4 #include <algorithm>
 5 #include <iostream>
 6 #include <cmath>
 7 using namespace std;
 8 #define pi 3.1415926
 9 #define e 2.718281828459
10 #define ll long long 
11 const int mod=1e8;
12 const int N=10000;
13 int main()
14 {
15     int n,i,j,m;
16     ll a[N]={1},c;
17     scanf("%d",&n);
18     m=0;
19     for(i=1;i<=n;i++){
20         c=0;
21         for(j=0;j<=m;j++){
22             a[j]=a[j]*i+c;
23             c=a[j]/mod;
24             a[j]%=mod;
25         }
26         if(c>0){
27             m++;
28             a[m]=c;
29         }
30     }
31     printf("%lld",a[m]);
32     for(i=m-1;i>=0;i--)
33         printf("%08lld",a[i]);
34     printf("\n");
35     return 0;
36 }