题目：
Once upon a time, there is a special coco-cola store. If you return three empty bottles to the shop, you‘ll get a full bottle of coco-cola to drink. If you have n empty bottles right in your hand, how many full bottles of coco-cola can you drink?
输入
There will be at most 10 test cases, each containing a single line with an integer n (1<=n<=100). The input terminates with n = 0, which should not be processed
输出
For each test case, print the number of full bottles of coco-cola that you can drink.
样例输入
3
10
81
0
样例输出
1
5
40
题意：3个空瓶子换一瓶可乐，注意2个空瓶子的时候，借一个空瓶子的情况。
AC code
#include<iostream> #include<cstdio> #include<cstring> #include<algorithm> using namespace std; int main() { int n; while(scanf("%d", &n),n){ int sum = 0; while(n>=2){ if(n ==2){ n++; }else{ sum += n/3; n = n/3+n%3; } } cout<<sum<<endl; } return 0; }
原文：http://www.cnblogs.com/lzeffort/p/6380321.html