merge_intervals.py

from pprint import pprint

def convert(date):
	day, hour = date.split(' à ')
	hour = int(hour.replace('h', ''))
	return day + '_' + str(hour).rjust(2, '0')

def merge(start, end, other_start, other_end):
	if other_start < start and other_end < start:
		return None
	if other_start <= start and start <= other_end <= end:
		return [other_start, end]
	if start <= other_start <= end and start <= other_end <= end:
		return [start, end]

intervals = [
 ('2020-07-17 à 12h', '2020-07-17 à 15h'),
 ('2020-07-17 à 17h', '2020-07-17 à 20h'),
 ('2020-07-17 à 14h', '2020-07-17 à 19h'), 
]

intervals = [(convert(start), convert(end)) for start, end in intervals]

while True:
	new_intervals = []

	for i, interval in enumerate(intervals):
		start, end = interval
		for j, other_interval in enumerate(intervals[i+1:]):
			other_start, other_end = other_interval

			result = merge(other_start, other_end, start, end)
			if not result:
				result = merge(start, end, other_start, other_end)
			if result:
				print('merge >')
				print('interval', interval, 'and', other_interval)
				print('result', result)
				print()
				intervals.pop(i)
				intervals.pop(i+j)
				intervals.append(result)
				new_intervals = intervals
				break
		if new_intervals:
			break
	if not new_intervals:
		break
	intervals = new_intervals

print('Final result >')
pprint(intervals)

"""
commence à 2020-07-17 à 12h
fini à 2020-07-17 à 20h
"""