题解 | #汽水瓶#

#include<iostream>
using namespace std;

//观察数据，取巧法
int CalcNuMber_1(int n)
{
    return n/2;
}

//概念法
int CalcNumber(int n)
{
    int sum=0;
    while(n>1)
    {
        int res=n/3;
        int left=n%3;
        sum+=res;
        n=left+res;
        if(n==2)
        {
            sum++;
            break;
        }
    }
    return sum;
}

int main()
{
    int n;
    while(cin>>n)
    {
        if(n==0)
        break;
        int res=CalcNuMber_1(n);
	  	//int res=CalcNumber(n);
        cout<<res<<endl;
    }
    return 0;
}