555
Op doesn't have time for interviews
(programming.dev)
Post:
You have three switches in one room and a single light bulb in another room. You are allowed to visit the room with the light bulb only once. How do you figure out which switch controls the bulb? Write your answer in the comments before looking at other answers.
Comment:
If this were an interview question, the correct response would be "Do you have any relevant questions for me? Because have a long list of things that more deserving of my precious time than to think about this!
Text ambiguous. Leave doors(s) between rooms open. Flip switches, see which one controls bulb in other room. No need to even visit other room. Done in seconds.
Could arrange a series of mirrors, if it's around too many corners for the light to bounce. Wedge any doors open if necessary. Thus another plausible zero-entry solution.
This also assumes youre alone, a practical person would send someone else in the other room and communicate the states back
It doesn't assume you're alone.
Don't even need to leave the door open. What door doesn't have enough of a gap to see if a light is on?