71 买卖椰子水

暴力贪心，注意找15块时优先选择10+5，其次是5+5+5

#include <iostream>using namespace::std;
using std::cout;
using std::cin;int main()
{int n;cin >> n;int bills[n+1];for(int i=1; i<=n; i++){cin >> bills[i];}int c5=0, c10=0;int flat=0;for(int i=1; i<=n; i++){if(bills[i] == 5){c5 = c5+1;}else if(bills[i] == 10){if(c5 >= 1){c5 = c5-1;c10 = c10+1;}else{flat = 1;i = n+1;}}else if(bills[i] == 20){if(c10 >= 1){if(c5 >= 1){c10 = c10-1;c5 = c5-1;}else{flat = 1;i = n+1;}}else{if(c5 >= 3){c5 = c5-3;}else{flat = 1;i = n+1;}}}}if(flat == 0){std::cout << "true";}else{std::cout << "false";}return 0;
}