89 lines
2.4 KiB
Python
89 lines
2.4 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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def readinput() -> list:
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with open("input", "r", encoding="utf-8") as file:
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lines = file.readlines()
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return lines
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def find_xmas(grid: list[list], x: int, y: int) -> int:
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height = len(grid) - 1
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width = len(grid[0]) - 1
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count = 0
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for searchstring in ["XMAS", "SAMX"]:
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# horizontal right
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if x + 3 <= width:
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found = sum(grid[y][x + i] == searchstring[i] for i in range(4))
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if found == 4:
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count += 1
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# vertical down
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if y + 3 <= height:
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found = sum(grid[y + i][x] == searchstring[i] for i in range(4))
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if found == 4:
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count += 1
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# diagonal down right
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if y + 3 <= height and x + 3 <= width:
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found = sum(grid[y + i][x + i] == searchstring[i] for i in range(4))
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if found == 4:
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count += 1
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# diagonal down left
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if y + 3 <= height and x - 3 >= 0:
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found = sum(grid[y + i][x - i] == searchstring[i] for i in range(4))
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if found == 4:
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count += 1
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return count
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def find_cross_mass(grid: list[list], x: int, y: int) -> int:
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# check clockwise for
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# M.M
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# .A.
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# S.S
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# then rotate the outer ring clockwise and check again
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for searchstring in ["MMSS", "SMMS", "SSMM", "MSSM"]:
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found = (
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grid[y - 1][x - 1] == searchstring[0]
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and grid[y - 1][x + 1] == searchstring[1]
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and grid[y + 1][x + 1] == searchstring[2]
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and grid[y + 1][x - 1] == searchstring[3]
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)
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if found:
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return 1
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return 0
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def main():
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grid = readinput()
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count = 0
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for y, _ in enumerate(grid):
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for x, _ in enumerate(grid[0]):
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pos = grid[y][x]
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if pos in ["X", "S"]:
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count += find_xmas(grid, x, y)
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print("XMAS count: %d" % count)
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count = 0
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for y in range(1, len(grid) - 1):
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for x in range(1, len(grid[0]) - 1):
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pos = grid[y][x]
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if pos == "A":
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count += find_cross_mass(grid, x, y)
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print("X-MAS count: %d" % count)
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if __name__ == "__main__":
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main()
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