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class Gear:
def __init__(self, line_idx, column_idx):
self.line_idx = line_idx
self.column_idx = column_idx
self.connecting_parts = []
def add_part_to_gear(line_idx, column_idx, part_number_line_idx, part_number_column_idx, gears):
for gear in gears:
if gear.line_idx == line_idx and gear.column_idx == column_idx:
gear.connecting_parts.append((part_number_line_idx, part_number_column_idx))
break
else:
new_gear = Gear(line_idx, column_idx)
new_gear.connecting_parts.append((part_number_line_idx, part_number_column_idx))
gears.append(new_gear)
def check_if_part_number(line_index, column_index, lines, gears):
ret_val = False
current_line = lines[line_index]
if column_index > 0 and current_line[column_index - 1] != ".":
if current_line[column_index - 1] == "*":
add_part_to_gear(line_index, column_index - 1, line_index, column_index, gears)
ret_val = True
max_column_index = column_index
for index in range(column_index + 1, len(current_line)):
if not current_line[index].isdigit():
break
max_column_index = index
if max_column_index + 1 < len(current_line) and current_line[max_column_index + 1] != ".":
if current_line[max_column_index + 1] == "*":
add_part_to_gear(line_index, column_index + 1, line_index, column_index, gears)
ret_val = True
min_other_column_index = max(column_index - 1, 0)
max_other_column_index = min(max_column_index + 1, len(current_line) - 1)
if line_index > 0:
other_line = lines[line_index - 1]
for current_column_index in range(min_other_column_index, max_other_column_index + 1):
other_char = other_line[current_column_index]
if not other_char.isdigit() and other_char != ".":
if other_char == "*":
add_part_to_gear(line_index - 1, current_column_index, line_index, column_index, gears)
ret_val = True
if line_index + 1 < len(lines):
other_line = lines[line_index + 1]
for current_column_index in range(min_other_column_index, max_other_column_index + 1):
other_char = other_line[current_column_index]
if not other_char.isdigit() and other_char != ".":
if other_char == "*":
add_part_to_gear(line_index + 1, current_column_index, line_index, column_index, gears)
ret_val = True
return ret_val
def main():
lines = []
positions = []
gears = []
with open("input", "r") as f:
for line in f:
lines.append(line.strip())
part_numbers = []
parsed_number = None
is_part_number_parsed = False
for line_index, line in enumerate(lines):
for column_index, char in enumerate(line):
if not char.isdigit():
if is_part_number_parsed:
part_numbers.append(int(parsed_number))
parsed_number = None
is_part_number_parsed = False
elif parsed_number is not None:
parsed_number += char
else:
parsed_number = char
is_part_number_parsed = check_if_part_number(line_index, column_index, lines, gears)
if is_part_number_parsed:
positions.append((line_index, column_index))
if is_part_number_parsed:
part_numbers.append(int(parsed_number))
parsed_number = None
is_part_number_parsed = False
gears = [gear for gear in gears if len(gear.connecting_parts) == 2]
ratios = []
for gear in gears:
ratios.append(part_numbers[positions.index(gear.connecting_parts[0])] * part_numbers[positions.index(gear.connecting_parts[1])])
print(sum(ratios))
if __name__ == '__main__':
main()
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