题解 | 汽水瓶

#include <stdio.h>

int bottles(int n);

int main() 
{
    int n;
    while(scanf("%d",&n) &&n != 0)
    {
        printf("%d\n",bottles(n));
    }

    return 0;
}

int bottles(int n)
{
    int total = 0;
    while(n > 2)
    {
        int k = n / 3;
        total =  total + k;
        n = n % 3 + k;
    }
    
    if(n == 2) total++;  
    
    return total;
}