import aocd

import math

def parse(data):
    return sorted(tuple(map(int, r.split('-'))) for r in data.split('\n\n')[0].strip().split('\n'))

def merge_overlapping(ranges):
    current_min = None
    current_max = -math.inf

    for new_min, new_max in ranges:
        if new_min > current_max:
            # Previous range is successfully merged
            if current_min is not None:
                # Previous range actually does exist
                yield (current_min, current_max)
            current_min = new_min
            current_max = new_max
        else:
            # Need to merge current range into previous
            # Use max() here to prevent (1, 10), (3, 7) from resolving to (1, 7), e.g.
            current_max = max(new_max, current_max)
    
    # Get the range that gets missed at the end
    yield (current_min, current_max)

def range_length(low, high):
    return high - low + 1

def main(data):
    ranges = parse(data)
    return sum(range_length(*r) for r in merge_overlapping(ranges))

if __name__ == '__main__':
    solution = main(aocd.get_data(day=5, year=2025))
    print(solution)
    aocd.submit(solution, part='b', day=5, year=2025)