Count the number of open lockers in school

Carvia Tech | May 19, 2019 | 1 min read | 109 views | Python Coding Problems


School Daze

A group of schools has a specific number of lockers and a specific number of students. All lockers are closed on the first day of school. As students get to school they begin to play with the lockers. The first student opens every locker. The second student begins with the 2nd locker and closes every other locker. The third student starts with the third locker and changes every 3rd locker. That is, the third student opens the locker if it is closed and closes it if it is open. The 4th student starts with locker 4 and changes every 4th locker and so on. After all the students are done, display how many lockers are open.

Test data
Input Output

100, 100

100 Lockers: 100 Students; 10 Open lockers

10, 5

10 Lockers; 5 Students; 6 Open lockers

1000, 50

1000 Lockers; 50 Students; 499 Open lockers

Get Open Lockers
def get_open_lockers(num_lockers, num_students):
    list_lockers = ["open"]*num_lockers # 1st step
    for k in range(2,num_students+1): # others
        for i,j in enumerate(list_lockers):
            if (i+1)>=(k-1):
                if (i+1)%k==0:
                    if list_lockers[i] == "open":
                        list_lockers[i] = "close"
                    else:
                        list_lockers[i] = "open"
    return list_lockers.count("open")


print(get_open_lockers(100, 100))
Output
10

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