源代码如下，为什么RE？

#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,k,j1=0,j2=0;
	long long sum1=0,sum2=0;
	cin>>n,k;
	for(int i=1;i<=n;i++){
		if(i%k==0){
			sum1+=i;
			j1++;
		}
		if(i%k==1){
			sum2+=i;
			j2++;
		}
	}
	long double s1=sum1/j1*1.0;
	long double s2=sum2/j2*1.0;
	cout<<setprecision(1)<<fixed<<s1<<" ";
	cout<<setprecision(1)<<fixed<<s2;
	return 0;
}