Problem P08. [算法课蛮力法] 柠檬水找零

多个判断，简单题

#include <iostream>
#include <bits/stdc++.h>

using namespace std;
int bills[3]={0};

int main()
{
    bool flag=true;
    while(1){
        int ret;
        int bill;
        ret = scanf("%d", &bill);
        if (ret==EOF){
            break;
        }
        if (bill==5){
            bills[1]++;
        }else if (bill==10&&bills[1]>0){
            bills[1]--;
            bills[2]++;
        }else if (bill==20&&bills[1]>0){
            if (bills[2]>0){
                bills[2]--;
                bills[1]--;
            }else if (bills[1]>2){
                bills[1]-=3;
            }else {
                flag = false;
                break;
            }
        }else {
            flag = false;
            break;
        }
    }
    if (flag==true){
        printf("true");
    }else {
        printf("false");
    }
    return 0;
}