72 lines
1.5 KiB
Python
72 lines
1.5 KiB
Python
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INPUT_FILE = "input.text"
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INSTRUCTIONS = []
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PATH = {}
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import math
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def read_file() -> None:
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with open(INPUT_FILE, 'r') as file:
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lines = file.readlines()
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line_index = 0
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for line in lines:
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# This in our instruction line
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if line_index == 0:
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for char in line:
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if char == 'L':
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INSTRUCTIONS.append(0)
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elif char == 'R':
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INSTRUCTIONS.append(1)
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elif line_index != 1:
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source: str = line.split('=')[0].strip()
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dest = line.split('=')[1].strip()[1:-1].split(', ')
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PATH[source] = dest
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line_index += 1
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def main() -> None:
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read_file()
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# print(PATH)
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# Find all starting positions (because we're a ghost in the 4th dimension)
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initial_positions = []
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for pos in PATH:
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if pos[2] == 'A':
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initial_positions.append(pos)
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# Find how many steps for each ghost to get to Z
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steps_to_finish = []
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for pos in initial_positions:
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steps = 0
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done = False
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while True:
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for instruction in INSTRUCTIONS:
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pos = PATH[pos][instruction]
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if pos[2] == 'Z':
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done = True
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break
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steps += 1
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if done:
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steps_to_finish.append(steps + 1)
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break
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print(f'Steps to finish: {math.lcm(*steps_to_finish)}')
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if __name__ == "__main__":
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main()
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