How to solve this problem?
You have n doors in a row that are all initially closed. You make n passes by the doors. The first
time through, you visit every door and toggle the door (if the door is closed, you open it; if it is
open, you close it). The second time you only visit every 2nd door (door #2, #4, #6, ...). The
third time, every 3rd door (door #3, #6, #9, ...), etc, until you only visit the nth door.
You need to find out what state are the doors in after the last pass? Which are open, which are
closed?
You'll be given number of doors, n.
You need to print out pair of (door_number, state) separated by '\n' aka 'end of line'. See
SAMPLE_OUTPUT for more clarity.
SAMPLE_INPUT:
3
SAMPLE_OUTPUT:
1,open
2,closed
3,closed |