Contest1260/D.cpp

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int n;
    while(cin>>n && n)
    {
        double sum = 0;
        if(n < 4) sum = 10;
        if(n >= 4 && n <= 8) sum = 10 + (n - 4) * 2;
        if(n > 8)
        {
            while(n >= 8)
            {
                sum += 18;
                n -= 8;
            }
            if(n <= 4)
            {
                sum += 2.4 * n;
            }
            else
            {
                sum += 10 + (n - 4) * 2;
            }
        }
        if(sum - (int)sum == 0)
            printf("%d\n", (int)sum);  //注意这里输出格式的切换
        else
            printf("%.1f\n", sum);
    }
    return 0;
}