40分的代码..如何改进

#include<iostream>
#include<iomanip>
using namespace std;
int main()
{
	int n,k;
	float a=0.0,b=0.0,num1=0.0,num2=0.0;
	cin>>n>>k;
	for(int i=1;i<=n;i++){
		if(i%k==0){
			a+=i;
			num1++;
		}else{
			b+=i;
			num2++;
		}
	}
	cout<<fixed<<setprecision(1)<<a/num1<<" "<<b/num2<<endl; 
	return 0;
 }