Discussion on Minimum Average Waiting Time Challenge

2 years ago+ 0 comments

I always prefer to give variables more meaningful names, and provide some comments. In my solution, currently_waiting is a heap of customers that already placed their orders, updated every loop.

import heapq

def minimumAverage(customers):
    # customers = [(order_time, cooking_time)]
    customers.sort()  # Sort by order time, then cooking time
    number_of_customers = len(customers)
    current_time = total_wait = 0
    currently_waiting = []
    while customers or currently_waiting:
        # Move to a heap of currently-waiting customers (as of `current_time`)
        while customers and customers[0][0] <= current_time:
            order_time, cooking_time = customers.pop(0)
            heapq.heappush(currently_waiting, (cooking_time, order_time))
        if not currently_waiting:
            # no orders yet, so fast forward to next customer
            current_time = customers[0][0]
            continue
        # Cook the order that will finish the sooner (first item on the heap)
        cooking_time, order_time = heapq.heappop(currently_waiting)
        total_wait += current_time + cooking_time - order_time
        current_time += cooking_time
    return total_wait // number_of_customers

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