Interview Question

Financial Software Developer Interview

I got stuck at the logic question, the answer didn't strike

  me at that time. The question was : There are 100 bulbs, all off at first. In the 1st round, all bulbs are switched on, in the second round every second bulb changes state, in the third round every third bulb changes state and so on. Which all bulb will be on at the end of 100th round?

Interview Answer

1 Answer


the answer is all the square numbers bulbs are on.

Xin Du on May 13, 2013

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