一元钱一瓶水，两个空瓶可以换一瓶，三个盖儿可以换一瓶，20元最多能喝多少?

#include<iostream>
using namespace std;
int countwater()
{
int sumprice=20;
int sumpz=0;
int sumpg=0;
int sum=0;
while((sumprice)||(sumpz>=2)||(sumpg>=3))
{
while(sumprice)
{
sumprice--;
sum++;
sumpz++;
sumpg++;
}
while((sumpz>=2))
{
int a=sumpz/2;
sumpz%=2;

sumprice+=a;
}
while((sumpg>=3))
{
int b=sumpg/3;
sumpg%=3;

sumprice+=b;
}
}

cout<<"剩下的瓶子数："<<sumpz<<endl;
cout<<"剩下的瓶盖数："<<sumpg<<endl;
return sum;
}
int main()
{
cout<<countwater();
return 0;
}