• #include<iostream> using namespace std; int main(){ int n; cin>>n; int ans=1; int sum=0; for(int i=1;i<=n;i++) { ans*=i; sum+=ans; } cout<<sum; }

#include<iostream> using namespace std; int main(){ int n; cin>>n; int ans=1; int sum=0; for(int i=1;i<=n;i++) { ans*=i; sum+=ans; } cout<<sum; }

#include <stdio.h> #include <iostream> using namespace std; int main() { int n; cin>>n; int ans =1; int sum =0; for(int i = 1 ; i <= n ; i++) { ans *=i; sum += ans; } cout<< sum << endl; }

#include <iostream>
#include <stdio.h>
#include <math.h>
#include <iomanip>
using namespace std;
int m , n , ans; 
int main()
{
	cin >> m >> n;
	for( int i = m ; i <= n ; i++ )
	{
		if( i % 17 == 0 )
		{
			ans += i;
		}
	}
	cout << ans;
    return 0;
}

兄弟们，为什么ans和sum不能开long long，int就行？大佬求解 longlong代码：（错的，不要复制）

#include <iostream>
#include <bits/stdc++.h>
using namespace std;
const int N=1e7+10;
const int INF=0x3f3f3f3f;
int main()
{
int n;
long long sum=1,ans;
cin>>n;
for(int i=1;i<=n;i++)
{
for(int j=1;j<=i;j++)
{
sum*=j;
}
ans+=sum;
sum=1;
}
cout<<ans;
}

int代码：

#include <iostream>
#include <bits/stdc++.h>
using namespace std;
const int N=1e7+10;
const int INF=0x3f3f3f3f;
int main()
{
	int n;
	int sum=1,ans;
	cin>>n;
	for(int i=1;i<=n;i++)
	{
		for(int j=1;j<=i;j++)
		{
			sum*=j;
		}
		ans+=sum;
		sum=1;
	} 
	cout<<ans;
}

#include<iostream> using namespace std; int n,ans,jc=1; int main(){

cin >> n;
for(int i = 1;i <= n;i++)
{ 
 	jc = 1; 
 	for(int j = 1;j <=i;j++)
    {
    	jc*=j;
	}
	ans +=jc;
}
cout<<ans;
return 0;

}

#include <iostream> #include <iomanip> using namespace std; int main() { int n,sum=0,m=1; cin>>n; for(int i=1; i<=n; i++)//常用i,j,k { m*=i; sum+=m; } cout<<sum; return 0; }

using namespace std;
int main()
{
    int n;
    cin >> n;
    int ans = 1;
    int jc=0 ;
    for (int i = 1; i <= n; i++)
    {
        ans *=i;
        jc += ans;
    }
    cout << jc;
}

#include <stdio.h>
#include <iostream>
using namespace std;
int main()
{
    int n;
    cin >> n;
    int ans = 1;
    int sum = 0;
    for (int i = 1; i <= n; i++)
    {
        ans *=i;
        sum += ans;
    }
    cout << sum << endl;
}

#include<bits/stdc++.h>
using namespace std;
int n;
long long jc(int n)
{
	if(n==1)return 1;
	long long sum=1;
	for(int i=2;i<=n;i++)sum*=i;
	sum+=jc(n-1);
	return sum;
}
int main()
{
	cin>>n;
	long long ans=jc(n);
	cout<<ans;
	return 0;
}

#include <iostream>
#include <math.h>
#include <iomanip>
using namespace std;
#define LL Long Long
const int N=1e5+10;
const int INF=0x3f3f3f3f;
int main()
{
	int n;
	cin >> n;
	int ans = 1;
	int sum = 0;
	for(int i = 1 ; i <= n ; i++)
	{
		ans *= i;
		sum += ans;
	}
	cout << sum << endl;
}

#include <stdio.h>
#include <iostream>
#include <math.h>
using namespace std;
int main()
{
	int n;
	cin>>n;
	int ans=1;
	int sum=0;
	for(int i=1;i<=n;i++)
	{
		ans*=i;
		sum+=ans;
	}
	cout<<sum;
}

打表义不容辞

#include<iostream> 
using namespace std; 
int n[13] = {0,1,2,6,24,120,720,5040,40320,362880,3628800,39916800,479001600};
int k, sum;
int main(){
    cin >> k;
	for(int i = 1; i <= k; i++){
        sum += n[i];
    }
    cout << sum;
    return 0;
}

#include <stdio.h>
#include <iostream>
using namespace std;
int main()
{
	int n;
	cin >> n;
	int ans = 1;
	int sum = 0;
	for(int i = 1 ; i <= n ; i++)
	{
		ans *= i;
		sum += ans;
	}
	cout << sum << endl;
}

#include <stdio.h>
#include <iostream>
using namespace std;
int main()
{
    int n;
    cin >> n;
    int ans = 1;
    int sum = 0;
    for (int i = 1; i <= n; i++)
    {
        ans *=i;
        sum += ans;
    }
    cout << sum << endl;
}