题目链接

贪心

class Solution {
    public boolean lemonadeChange(int[] bills) {
        if(bills[0] == 10 || bills[0] == 20 || bills[1] == 20){
            return false;
        }
        int count5 = 1;
        int count10 = 0;
        for(int i = 1; i < bills.length; i++){
            if(bills[i] == 5){
                count5++;
            }
            if(bills[i] == 10){
                count10++;
                if(count5 >= 1){
                    count5--;
                }else{
                    return false;
                }
            }   
            if(bills[i] == 20){
                if(count10 >= 1){
                    if(count5 >= 1){
                        count10--;
                        count5--;
                    }else{
                        return false;
                    }
                }else{
                    if(count5 >= 3){
                        count5 = count5 - 3;
                    }else{
                        return false;
                    }
                }
            }
        }
        return true;
    }
}