第34周赛

 

#include<bits/stdc++.h>
using namespace std;
const int N=10000;
int n,sum=1;
int main()
{
    int sum1=0,sum2=0,sum3=0;
    cin>>n;
    for(int i=0; i<n; i++)
    {
        int a[N],b[N],c[N];
            cin>>a[i]>>b[i]>>c[i];
            sum1+=a[i];
            sum2+=b[i];
            sum3+=c[i];
    }
    if(sum1==0&&sum2==0&&sum3==0)
        cout<<"YES"<<endl;
    else
        cout<<"NO"<<endl;
    return 0;
}

 

 

#include<bits/stdc++.h>
using namespace std;
const int N=10000;
int n,q,m,sum;
int a[N];
int main()
{
    cin>>m;
    for(int i=2; i<m; i++)
    {
        int n=m;
        while(n)
        {
            q= n % i;
            sum+=q;
            n /= i;
        }
    }
    int p=m-2;
    for(int i=2;i<=p;i++)
    {
        if(sum%i==0&&p%i==0)
        {
            sum/=i;
            p/=i;
            i--;
        }
    }
    cout<<sum<<"/"<<p<<endl;

}