#include <stack>
#include <stdio.h>
#include <iostream>
#include <vector>
#include <iomanip>
#include <string.h>
#include <algorithm>
#include<bits/stdc++.h>
using namespace std;
const int N=1e6+10;
int ans[N], len=1;
void a(int x){
	
	for(int i=0; i<len; i++){
		ans[i] *= x;
	}
	for(int i=0; i<len; i++){
		ans[i+1]+=ans[i]/10000;
		ans[i]%=10000;
		
	}
	while(ans[len]!=0){
		ans[len+1]+=ans[len]/10000;
		ans[len]%=10000;
		len ++;
		
	}
}
int main(){
	int n;
	cin >> n;
	ans[0]=1;
    for (int i=2; i<=n; i++){
    	a(i);
    }
    len --;
    cout << ans[len];
    for(int i=len-1; i>=0; i--){
    	printf("%04d",ans[i]);
    }
    return 0;
}//最后的输出采用格式化输出，超格，而前面不需要格式化输入

40分代码（别看） #include<iostream>

using namespace std;

int main()

{

int n,sum=1;

cin>>n;

if(n!=0){

for(int i=1;i<=n;i++){

sum=sum*i;}cout<<sum;}else{cout<<1;}

return 0;

}

#include<bits/stdc++.h>
using namespace std;
const int N=1e6+10;
int ans[N], len=1;
void a(int x){
	
	for(int i=0; i<len; i++){
		ans[i] *= x;
	}
	for(int i=0; i<len; i++){
		ans[i+1]+=ans[i]/10000;
		ans[i]%=10000;
		
	}
	while(ans[len]!=0){
		ans[len+1]+=ans[len]/10000;
		ans[len]%=10000;
		len ++;
		
	}
}
int main(){
	int n;
	cin >> n;
	ans[0]=1;
    for (int i=2; i<=n; i++){
    	a(i);
    }
    len --;
    cout << ans[len];
    for(int i=len-1; i>=0; i--){
    	printf("%04d",ans[i]);
    }
	return 0;
} 

#include<stack>
#include<stdio.h>
#include<iostream>
#include<cstdio>
#include<vector>
#include<iomanip>
#include<string.h>
#include<math.h>
#include<iostream>
#include<bits/stdc++.h>
using namespace std;
const int N=1e6+10;
int ans[N],len=1;
void mul(int x)
{
	for(int i=0;i<len;i++)ans[i]*=x;
	for(int i=0;i<len;i++)
	{
		ans[i+1]+=ans[i]/10000;
		ans[i]%=10000;
	}
	while(ans[len]!=0)
	{
		ans[len+1]=ans[len]/10000;
		ans[len]%=10000;
		len++;
	}
}
int main()
{
	int n;
	cin>>n;
	ans[0]=1;
	for(int i=2;i<=n;i++)mul(i);
	len--;
	cout<<ans[len];
	for(int i=len-1;i>=0;i--)printf("%04d",ans[i]);
	return 0;
}
//nima

#include<bits/stdc++.h>
using namespace std;
const int N=1e6+10;
int ans[N],len=1;
void mul(int x)
{
	for(int i=0;i<len;i++)ans[i]*=x;
	for(int i=0;i<len;i++)
	{
		ans[i+1]+=ans[i]/10000;
		ans[i]%=10000;
	}
	while(ans[len]!=0)
	{
		ans[len+1]=ans[len]/10000;
		ans[len]%=10000;
		len++;
	}
}
int main()
{
	int n;
	cin>>n;
	ans[0]=1;
	for(int i=2;i<=n;i++)mul(i);
	len--;
	cout<<ans[len];
	for(int i=len-1;i>=0;i--)printf("%04d",ans[i]);
	return 0;
}

#include <queue>
#include <math.h>
#include <stack>
#include <stdio.h>
#include <iostream>
#include <vector>
#include <iomanip>
#include <string.h>
#include <algorithm>
using namespace std;
#define LL long long
const int N = 1e4 + 10;
const int INF = 0x3f3f3f3f;
long long len = 1 , a[N];
void mul(long long x)
{
	for(int i = 0 ; i < len ; i++)
		a[i] *= x;
	for(int i = 0 ; i < len ; i++)
	{
		a[i+1] += a[i]/10000;
		a[i] %= 10000;
	}
	while(a[len] != 0)
	{
		a[len+1] = a[len]/10000;
		a[len] %= 10000;
		len++; 
	}
}
int main()
{
	int n;
	cin >> n;
	a[0] = 1;
	for(int i = 2 ; i <= n ; i++)
		mul(i);
	len--;
	cout << a[len];
	for(int i = len-1; i >= 0 ; i--)
		printf("%04d",a[i]);
	return 0;
}

#include <queue> #include <stack> #include <vector> #include <math.h> #include <iomanip> #include <stdio.h> #include <iostream> #include <string.h> #include <algorithm> using namespace std; #define LL long long #define D double const int N=1e6+10; const int INF=0x3f3f3f3f; int len=1,a[N]; void mul(int x) { for(int i=0;i<len;i++) a[i]*=x; for(int i=0;i<len;i++) { a[i+1]+=a[i]/10000; a[i]%=10000; } while(a[len]!=0) { a[len+1]=a[len]/10000; a[len]%=10000; len++; } } int main() { int n; cin>>n; a[0]=1; for(int i=2;i<=n;i++) mul(i); len--; cout<<a[len]; for(int i=len-1;i>=0;i--) printf("%04d",a[i]); return 0; }

#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 10;
const int INF = 0x3f3f3f3f;
int a[N],len = 1;
void mul(int p)
{
	int k = 0;
	for(int i = 0;i < len;i++)
	{
		a[i] =a[i]*p+k;
		k = a[i]/10000;
		a[i] %= 10000;
	}
	while(k!=0)
	{
		a[len++] = k%10000;
		k = k /10000;
	}
}
int main()
{
	int n;
	cin >> n;
	a[0]=1;
	for(int i=2;i <= n;i++)
		mul(i);
	cout << a[len-1];
	len-=2;
	for(int i=len;i>=0;i--)
		printf("%04d",a[i]);
	return 0;
}

//确保AC #include <iostream> #include <cstdio> using namespace std; int a[100010] = {1}; int len = 0; int n; void f(int x) { int k = 0; for(int i = 0; i <= len; i++) { a[i] = a[i] * x + k; k = 0; if(a[i] >= 10000) { k = a[i] / 10000; a[i] %= 10000; } } while(k != 0) { a[++len] = k % 10000; k = k / 10000; } return; } int main() { cin >> n; for (int i = 1; i <= n; i++) f(i); cout << a[len]; for(int i = len - 1; i >= 0; i--) printf ("%04d", a[i]); return 0; }