Day 13: Claw Contraption

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FAQ

  • Sparrow_1029@programming.dev
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    1 day ago

    I did run your code as-is in an ipython REPL to check. These were the results:

    REPL session
    # With unmodified `main` function & `import string` not shown
    In [4]: with open("inputs/day13.txt", "r") as f:
       ...:     input_data = f.read().strip().replace(',', '').split('\n\n')
       ...:
    
    In [5]: part_one, part_two = main(input_data)
    
    In [6]: part_one
    Out[6]: 39748
    
    In [7]: part_two
    Out[7]: 74926346266863
    
    # Then I modified the function to check if x is fractional
    In [8]: def main(input_data):
       ...:     part1_total_cost = 0
       ...:     part2_total_cost = 0
       ...:     for machine in input_data:
       ...:         Ax,Ay,Bx,By,Px,Py = [ int(l[2:]) for l in machine.split() if l[-1] in string.digits ]
       ...:         y,r = divmod((Ay * Px - Ax * Py), (Ay * Bx - Ax * By))
       ...:         if r == 0:
       ...:             x = (Px - Bx * y) / Ax
       ...:             if x % 1 == 0:
       ...:                 part1_total_cost += 3*x + y
       ...:         y,r = divmod((Ay * (Px+10000000000000) - Ax * (Py+10000000000000)), (Ay * Bx - Ax * By))
       ...:         if r == 0:
       ...:             x = ((Px+10000000000000) - Bx * y) / Ax
       ...:             if x % 1 == 0:
       ...:                 part2_total_cost += 3*x + y
       ...:
       ...:     return part1_total_cost,part2_total_cost
       ...:
    
    In [9]: part_one, part_two = main(input_data)
    
    In [10]: part_one
    Out[10]: 39748.0
    
    In [11]: part_two
    Out[11]: 74478585072604.0  # Correct answer for pt 2 of my input
    

    If you’re curious to check against my puzzle input, it’s here

    Thank you again for the back & forth, and for sharing your solution!

    • Acters@lemmy.world
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      22 hours ago

      there is exactly ONE “machine” that causes your result to be incorrect. ONLY for part 2.

      Button A: X+67, Y+67
      Button B: X+16, Y+73
      Prize: X=4877, Y=7214
      

      I see now what your corner case causes. so when my script solves for y first. it will be exact. BUT when you solve for x, it will be not divisible… makes sense now. I didn’t expect this. This only occurs because of part 2! so dastardly. well, that was interesting. I guess I am forced to add that extra check… rip those microsecond gains.