Day 7: Bridge Repair

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)
  • You can send code in code blocks by using three backticks, the code, and then three backticks or use something such as https://topaz.github.io/paste/ if you prefer sending it through a URL

FAQ

  • stevenviola@programming.devEnglish
    2·
    20 days ago

    Python

    Takes ~5.3s on my machine to get both outputs. Not sure how to optimize it any further other than running the math in threads? Took me longer than it should have to realize a lot of unnecessary math could be cut if the running total becomes greater than the target while doing the math. Also very happy to see that none of the inputs caused the recursive function to hit Python’s max stack depth.

    Code 
    import argparse
import os


class Calibrations:
    def __init__(self, target, operators) -> None:
        self.operators = operators
        self.target = target
        self.target_found = False

    def do_math(self, numbers, operation) -> int:
        if operation == "+":
            return numbers[0] + numbers[1]
        elif operation == "*":
            return numbers[0] * numbers[1]
        elif operation == "||":
            return int(str(numbers[0]) + str(numbers[1]))

    def all_options(self, numbers, last) -> int:
        if len(numbers) < 1:
            return last
        for j in self.operators:
            # If we found our target already, abort
            # If the last value is greater than the target, abort
            if self.target_found or last > self.target:
                return
            total = self.all_options(
                numbers[1:], self.do_math((last, numbers[0]), j)
            )
            if total == self.target:
                self.target_found = True

    def process_line(self, line) -> int:
        numbers = [int(x) for x in line.split(":")[1].strip().split()]
        self.all_options(numbers[1:], numbers[0])
        if self.target_found:
            return self.target
        return 0


def main() -> None:
    path = os.path.dirname(os.path.abspath(__file__))
    parser = argparse.ArgumentParser(description="Bridge Repair")
    parser.add_argument("filename", help="Path to the input file")
    args = parser.parse_args()
    sum_of_valid = [0, 0]
    with open(f"{path}/{args.filename}", "r") as f:
        for line in f:
            line = line.strip()
            target = int(line.split(":")[0])
            for idx, ops in enumerate([["+", "*"], ["+", "*", "||"]]):
                c = Calibrations(target, ops)
                found = c.process_line(line)
                sum_of_valid[idx] += found
                if found:
                    break
    for i in range(0, 2):
        part = i + 1
        print(
            "The sum of valid calibrations for Part "
            + f"{part} is {sum(sum_of_valid[:part])}"
        )


if __name__ == "__main__":
    main()

    https://github.com/stevenviola/advent-of-code-2024

    • iAvicenna@lemmy.world
      2·
      19 days ago

      If you havent already done so, doing it in the form of “tree search”, the code completes in the blink of an eye (though on a high end cpu 11th Gen Intel® Core™ i7-11800H @ 2.30GHz). posted the code below

      • stevenviola@programming.dev
        1·
        20 days ago

        Thanks! yup, I figured there would be a way. You’re right, much faster, on my machine with your code, this is the speed:

        $ time python3 day7.py 
4555081946288
227921760109726

real    0m0.171s

        I’ll have to take a look to understand how that works to be better.

        • Acters@lemmy.world
          1·
          19 days ago

          I posted my solution here and found my way to finish 30 milliseconds faster.(~100ms for his, and ~66 ms for mine) However, as I noted I stop prematurely sometimes. Which seems to work with my given input. but here is the one that makes sure it gets to the end of the list of integers:

          code 
          def main(input_data):
    input_data = input_data.replace('\r', '')
    parsed_data = {int(line[0]): [int(i) for i in line[1].split()[::-1]] for line in [l.split(': ') for l in input_data.splitlines()]}
    part1 = 0
    part2 = 0
    for item in parsed_data.items():
        root, num_array = item
        part_1_branches = [set() for _ in range(len(num_array)+1)]
        part_2_branches = [set() for _ in range(len(num_array)+1)]
        part_1_branches[0].add(root)
        part_2_branches[0].add(root)
        for level,i in enumerate(num_array):
            if len(part_1_branches[level]) == 0 and len(part_2_branches[level]) == 0:
                break

            for branch in part_1_branches[level]:
                if level==len(num_array)-1:
                    if branch == i:
                        part1 += root
                        break
                if branch % i == 0:
                    part_1_branches[level+1].add(branch//i)
                if branch - i > 0:
                    part_1_branches[level+1].add(branch-i)

            for branch in part_2_branches[level]:
                if level==len(num_array)-1:
                    if (branch == i or str(branch) == str(i)):
                        part2 += root
                        break
                if branch % i == 0:
                    part_2_branches[level+1].add(branch//i)
                if branch - i > 0:
                    part_2_branches[level+1].add(branch-i)
                if str(i) == str(branch)[-len(str(i)):]:
                    part_2_branches[level+1].add(int(str(branch)[:-len(str(i))].rjust(1,'0')))
    
    print("Part 1:", part1, "\nPart 2:", part2)
    return [part1, part2]

if __name__ == "__main__":
    with open('input', 'r') as f:
        main(f.read())