day_19.py

import re
from datetime import datetime

time_start = datetime.now()


with open('day_19.input', 'r') as file:
    lines = file.readlines()

# Function to count the number of ways to match the pattern
def count_ways(linen, patterns):
    count = [0 for _ in range(len(linen) + 1)]
    # We can reach the start of the string in 1 way this is linen[0:0]
    count[0] = 1

    # From the start of the string
    for index in range(len(linen)):
        # Check if the pattern is at the start
        for pattern in patterns:
            if linen[index:index + len(pattern)] == pattern:
                # If it matches the amount of ways to reach this index + the size of the match
                # is added with the amount of ways to reach the previous step (index)
                count[index + len(pattern)] += count[index]

    # This will be the amount of ways we can reach the end of the string
    return count[len(linen)]

CHARACTER_REGEX = r"[a-z]+"
regex_linen_matcher = r"\b(?:"
linen_patterns = []
for v in re.findall(CHARACTER_REGEX, lines[0]):
    regex_linen_matcher += v + r"|"
    linen_patterns.append(v)
regex_linen_matcher = regex_linen_matcher[:-1] + r")+\b"

part1 = 0
part2 = 0
for i in range(2, len(lines)):
    linen = lines[i][:-1]
    match = re.fullmatch(regex_linen_matcher, linen)
    if match:
        part1 += 1
        part2 += count_ways(linen, linen_patterns)

print("Part1", part1)
print("Part2", part2)

print("Total time: ", datetime.now() - time_start)
#Total time:  0:00:01.659790