Thee Supermarket Queue

There is a queue for the self-checkout tills at the supermarket. Your task is write a function to calculate the total time required for all the customers to check out!

input

• customers: an array of positive integers representing the queue. Each integer represents a customer, and its value is the amount of time they require to check out.
• n: a positive integer, the number of checkout tills.

output

The function should return an integer, the total time required.

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Important

Please look at the examples and clarifications below, to ensure you understand the task correctly :)

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Examples

queue_time([5,3,4], 1)
# should return 12
# because when n=1, the total time is just the sum of the times

queue_time([10,2,3,3], 2)
# should return 10
# because here n=2 and the 2nd, 3rd, and 4th people in the 
# queue finish before the 1st person has finished.

queue_time([2,3,10], 2)
# should return 12

Clarifications

• There is only ONE queue serving many tills, and
• The order of the queue NEVER changes, and
• The front person in the queue (i.e. the first element in the array/list) proceeds to a till as soon as it becomes free.

N.B. You should assume that all the test input will be valid, as specified above.

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def queue_time(customers, n):
    if customers==[]:
        return 0
    if len(customers)<=n:
        return max(customers)
    count=0
    while customers!=[]:
        for i in range(min(n, len(customers) )):
            customers[i]=customers[i]-1
        while 0 in customers:
            customers.remove(0)
        count+=1
    return count