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Cake day: July 12th, 2023

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  • My Python solution for part 1 and part 2. I really practice my regex skills.

    spoiler
    #!/usr/bin/python3
    
    import re
    
    value_re = '(\d+)'
    symbol_re = '[^\d.]'
    gear_re = '(\*)'
    
    def main():
        input = list()
        with open("input.txt", 'r') as in_file:
            for line in in_file:
                input.append(line.strip('\n'))
        length = len(input)
        width = len(input[0])
        value_sum = 0
        for idx, line in enumerate(input):
            for match in re.finditer(value_re, line):
                for line_mask in input[max(idx - 1, 0):min(idx + 2, length)]:
                    valid_chars = line_mask[max(match.span()[0] - 1, 0):min(match.span()[1] + 1, width)]
                    if re.search(symbol_re, valid_chars):
                        value_sum += int(match[0])
                        break
        print(f"Value sum = {value_sum}")
    
        gear_ratio = 0
        for idx, line in enumerate(input):
            for match in re.finditer(gear_re, line):
                valid_lines = input[max(idx - 1, 0):min(idx + 2, length)]
                min_range = max(match.span()[0] - 1, 0)
                max_range = min(match.span()[1], width)
                num_of_adjacent = 0
                temp_gear_ratio = 1
                for valid_line in valid_lines:
                    for match in re.finditer(value_re, valid_line):
                        if match.span()[0] in range(min_range,max_range + 1) or match.span()[1] - 1 in range(min_range,max_range + 1):
                            num_of_adjacent += 1
                            temp_gear_ratio *= int(match[0])
                if num_of_adjacent == 2:
                    gear_ratio += temp_gear_ratio
        print(f"Gear ratio = {gear_ratio}")
    
    if __name__ == '__main__':
        main()