day03/solution_gpt-4o.py

import re

def parse_instructions(memory):
    # Regular expression to find valid mul(X,Y) instructions
    mul_pattern = re.compile(r'mul\((\d{1,3}),(\d{1,3})\)')
    # Regular expression to find do() and don't() instructions
    do_pattern = re.compile(r'do\(\)')
    dont_pattern = re.compile(r"don't\(\)")

    # Find all mul instructions
    mul_matches = mul_pattern.finditer(memory)
    
    # Find all do() and don't() instructions
    do_matches = list(do_pattern.finditer(memory))
    dont_matches = list(dont_pattern.finditer(memory))
    
    # Sort do and don't matches by their start position
    control_matches = sorted(do_matches + dont_matches, key=lambda m: m.start())
    
    # Part 1: Sum of all valid mul instructions
    part1_sum = 0
    for match in mul_matches:
        x, y = int(match.group(1)), int(match.group(2))
        part1_sum += x * y
    
    # Part 2: Sum of enabled mul instructions
    part2_sum = 0
    mul_matches = mul_pattern.finditer(memory)  # Re-iterate over mul matches
    enabled = True  # Initially, mul instructions are enabled
    control_index = 0
    
    for match in mul_matches:
        # Check if there are any control instructions before this mul
        while control_index < len(control_matches) and control_matches[control_index].start() < match.start():
            if control_matches[control_index].group() == 'do()':
                enabled = True
            elif control_matches[control_index].group() == "don't()":
                enabled = False
            control_index += 1
        
        if enabled:
            x, y = int(match.group(1)), int(match.group(2))
            part2_sum += x * y
    
    return part1_sum, part2_sum

# Read the input file
with open('input.txt', 'r') as file:
    memory = file.read()

# Get the results for both parts
result1, result2 = parse_instructions(memory)

# Print the results
print(result1)
print(result2)