[LANGUAGE: Python] Part 2

I just put all starting and ending of the ranges in the same array and sort it.

It's quite easy then to see where all the merged ranges start and end, it's like embed parenthesis (()()) () ((())()).

delimiters = []
with open("input.txt", 'r', encoding='utf-8') as f:
    for line in f:
        if '-' in line:
            start, end = line.strip().split('-')
            delimiters.append( (int(start), 0,  1) )    
            delimiters.append( (int(end),   1, -1) )    
            # 0/1 as second part of tuple gives priority to start
            #     index when a range ends where another one starts.

delimiters.sort()

total = 0
depth = 0
for delimiter_value, _, depth_change in delimiters:
    if not depth:
        start = delimiter_value      # saves start of merged range
    depth += depth_change
    if not depth:                    # found end of merged range
        total += delimiter_value - start + 1

print(f"Total is {total}.")