阶乘之和 高精度

#include<iostream>
#include<cstring>
using namespace std;
int a[100000],n,i,y,xy[100000];
int main()
{
cin>>n;
a[0]=1;
a[1]=1;
for (y=1;y<=n;y++)
{
memset(xy,0,sizeof(xy));
xy[0]=a[0];
for (i=1;i<=a[0];i++)
{
xy[i]+=a[i]*y;
xy[i+1]=xy[i]/10;
xy[i]%=10;
}
while (xy[xy[0]+1]>0)
{
xy[xy[0]+2]=xy[xy[0]+1]/10;
xy[xy[0]+1]%=10;
xy[0]++;
}
for(i=1;i<=xy[0];i++) a[i]=xy[i];
a[0]=xy[0];
}
for (i=a[0];i>=1;i--) cout<<a[i];
cout<<endl;
return 0;
}