剩肥肥没钱去餐厅吃饭了
乖乖出门坐一个小时车去当帕鲁
:(
def averageWaitingTime(self, customers: List[List[int]]) -> float:
    finish_t = 0
    waiting_sum = 0
    for c in customers:
        finish_t = max(finish_t+c[1], c[0]+c[1])
        waiting_sum += (finish_t-c[0])
    return waiting_sum/len(customers)