By: Puzzle – Set 1 – Lets Code

Puzzle – Set 1 – Lets Code — Tue, 31 Jan 2017 15:48:37 +0000

[…] There are N doors in a row, numbered from 1 to N. Initially all are closed. Then you make N passes by N doors. In first pass you toggle (open the door if it is closed and close it if it is opened) all the doors starting from the first door. In the second pass you toggle every door whose number is a multiple of 2 (2, 4, 6, 8, 10…). In 3rd pass you toggle doors whose number is multiple of 3 (3, 6, 9, ..) and so on.. In the i‘th pass you toggle all the doors which are multiple of i. What will be the state of k‘th door after all the passes? […]

Comments on: N Doors Puzzle

By: Puzzle – Set 1 – Lets Code