860. 柠檬水找零

860. 柠檬水找零

class Solution {
    public boolean lemonadeChange(int[] bills) {
        int count_5 = 0;
        int count_10 = 0;
        int count_20 = 0;
        for(int i = 0;i < bills.length ;i++){
            if(bills[i] == 5){
                count_5++;
            }else if(bills[i] == 10){
                count_10++;
                count_5--;
            }else if(bills[i] == 20){
                if(count_10 > 0){
                    count_10--;
                    count_5--;
                }else{
                    count_5 -= 3;
                }
            }
            if(count_5 < 0){
                return false;
            }
        }
        return true;
    }
}