4 ms·

I know you’re joking, but apparently it was given as a programming problem in a contest on at least one occasion. See here: http://www.njohnston.ca/2014/08/obv

• robinhouston 8y ago
  Here’s another more recent case where it appeared in a coding contest: https://discuss.codechef.com/questions/133115/wrong-problem-in-the-contest-coding-hours https://discuss.codechef.com/questions/133115/wrong-problem-...
• bootsz 8y ago
  It's not a joke: https://leetcode.com/problems/cracking-the-safe/ https://leetcode.com/problems/cracking-the-safe/ It has been asked in real interviews
  • robinhouston 8y ago
    That’s a different (rather easier) problem: note that the safe combination can contain the same digit more than once. The solution to this problem is given by de Bruijn sequences: https://en.wikipedia.org/wiki/De_Bruijn_sequence https://en.wikipedia.org/wiki/De_Bruijn_sequence
    • bootsz 8y ago
      Ah, I see. Thanks