69 lines
1.8 KiB
Python
69 lines
1.8 KiB
Python
#!/usr/bin/env python
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# -*- encoding: utf-8; py-indent-offset: 4 -*-
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# Author: Sebastian Mark
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# CC-BY-SA (https://creativecommons.org/licenses/by-sa/4.0/deed.de)
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# pylint: disable=missing-module-docstring,missing-function-docstring,consider-using-f-string
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import re
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def readinput():
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with open("input", "r", encoding="utf-8") as file:
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lines = [line.rstrip("\n") for line in file.readlines()]
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return lines
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def find_numbers(lines: list) -> set:
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# create a set of [(y,x,number),(y,x,number)]
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numbers = set()
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for y, line in enumerate(lines):
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matches = re.finditer(r"\d+", line)
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for match in matches:
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x = match.start()
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numbers.add((y, x, match.group()))
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return numbers
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def check_partnumber(lines: list, starty: int, startx: int, partnumber: str) -> bool:
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directions = [
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(-1, 0), # Up
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(-1, 1), # Up-right
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(0, 1), # Right
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(1, 1), # Down-right
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(1, 0), # Down
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(1, -1), # Down-left
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(0, -1), # Left
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(-1, -1), # Up-left
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]
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width = len(lines[0])
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height = len(lines)
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for charpos in range(
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startx, startx + len(partnumber)
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): # for all numbers in the partnumber
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for dy, dx in directions: # check all directions
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nxty, nxtx = starty + dy, charpos + dx # new checkposition
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if 0 <= nxtx < width and 0 <= nxty < height: # validate borders
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if lines[nxty][nxtx] not in "0123456789.":
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return True # found symbol, this is a valid partnumber
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return False
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def main():
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lines = readinput()
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numbers = find_numbers(lines)
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# part 1
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count = 0
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for y, x, number in numbers:
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if check_partnumber(lines, y, x, number):
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count += int(number)
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print("Sum of partnumbers: %d" % count)
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if __name__ == "__main__":
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main()
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