50 lines
1.5 KiB
Python
50 lines
1.5 KiB
Python
import string
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import sys
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from collections import defaultdict
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lines = list(filter(bool, sys.stdin.read().split("\n")))
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values: list[int] = []
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gears: dict[tuple[int, int], list[int]] = defaultdict(list)
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for i, line in enumerate(lines):
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j = 0
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while j < len(line):
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# skip everything until a digit is found (start of a number)
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if line[j] not in string.digits:
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j += 1
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continue
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# extract the range of the number and its value
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k = j + 1
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while k < len(line) and line[k] in string.digits:
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k += 1
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value = int(line[j:k])
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# lookup around the number if there is a symbol - we go through the number
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# itself but that should not matter since it only contains digits
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found = False
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for i2 in range(max(0, i - 1), min(i + 1, len(lines) - 1) + 1):
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for j2 in range(max(0, j - 1), min(k, len(line) - 1) + 1):
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assert i2 >= 0 and i2 < len(lines)
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assert j2 >= 0 and j2 < len(line)
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if lines[i2][j2] != "." and lines[i2][j2] not in string.digits:
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found = True
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if lines[i2][j2] == "*":
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gears[i2, j2].append(value)
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if found:
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values.append(value)
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# continue starting from the end of the number
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j = k
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answer_1 = sum(values)
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answer_2 = sum(v1 * v2 for v1, v2 in filter(lambda vs: len(vs) == 2, gears.values()))
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print(f"answer 1 is {answer_1}")
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print(f"answer 2 is {answer_2}")
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