题解 | #汽水瓶#

#include <stdio.h>
#include <string.h>

#define MAX 1000

int main (){

    int num[MAX] = {0};
    int p, n = 0;
    while(scanf("%d", &num[n++]) != -1){
        if(num[n - 1] == 0)
            break;
    }
    for(int i = 0; i < n - 1; i++){
        p = 0;
        while(num[i] != 2){
            if(num[i] == 1)
                break;
            else if(num[i] ==0)
                return 0;
            p += num[i] / 3;
            num[i] = num[i] / 3 + num[i] % 3;
        }
        if(num[i] == 2)
            p++;
        printf("%d\n", p);
    }        
    

    return 0;
}