Day 6: Guard Gallivant

Megathread guidelines

  • Keep top level comments as only solutions, if you want to say something other than a solution put it in a new post. (replies to comments can be whatever)
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FAQ

  • @TunaCowboy
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    15 days ago

    Mine was 9s

    That’s about how long it takes for my python solution to complete.

    • @[email protected]OPM
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      fedilink
      25 days ago

      How did you detect loops? I just ran for 100000 steps to see if I escaped, got my time down to 3s by doing only 10000 steps.

      • @TunaCowboy
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        2
        edit-2
        5 days ago

        I added each visited position/direction to a set, and when a ‘state’ is reached again you have entered a loop:

        v = set()
        while t[g.r][g.c] != 'X':
            state = (g.r, g.c, g.d)
            if state in v:
                acc += 1
                break
            v.add(state)
            g.move(t)
        

        You can view my full solution here.

      • @Leavingoldhabits
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        25 days ago

        Not who you asked but: I save coordinates and direction into a vector each time the guard faces a #. Also every time the guard faces a #, I check if the position exists in the vector, if true, it’s an infinite loop. 78ms rust aolution.

        • @[email protected]OPM
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          fedilink
          15 days ago

          That’s probably quite optimal, compared with checking every state in the path, or running off a fixed number of steps