Advent of Code 2015 - Day 07 - Python

day07.py

import os, re
 
 # Based on AOC day 5
 
class PuzzleBase:
 
    @classmethod
    def parse_input(cls, puzzle_input):
        lines = []
        for line in puzzle_input.splitlines():
            lines.append(line.strip())
        return lines
 
    @classmethod
    def solve(cls, puzzle_input):
        strings = cls.parse_input(puzzle_input)
        num_nice_strings = 0
        for string in strings:
            if cls.is_a_nice_string(string):
                num_nice_strings += 1
        return num_nice_strings
 
    @classmethod
    def is_a_nice_string(cls, string):
        raise NotImplementedError("You must override this method in subclasses")
 
 
class Part1(PuzzleBase):
 
    @classmethod
    def is_a_nice_string(cls, string):
        # Process the input as a stream of characters
        # Convert the chars to lower case just in case?
        # First requirement:
        #   - For each char, increment a count for the number of vowels
        #   - If count < 3, return False
        vowel_count = 0
        for c in string:
            if c in "aeiou":
                vowel_count += 1
        if vowel_count < 3:
            return False
        # Second requirement:
        #   - Break the string into a series of inclusive 2-tuples
        #   - For each 2-tuple, see if the tuple consists of two identical characters
        #   - If not, return False
        has_double_char = False
        prev_char = string[0]
        for c in string[1:]:
            if c == prev_char:
                has_double_char = True
                break
            else:
                prev_char = c
        if not has_double_char:
            return False
        
        # Third requirement:
        #   - If any of ["ab", "cd", "pq", "xy"] are a substring, return False
        substring_list = ["ab", "cd", "pq", "xy"]
        contains_substrings = any(substring in string for substring in substring_list)
        if contains_substrings:
            return False
    
        return True
 
 
class Part2(PuzzleBase):
 
    @classmethod
    def is_a_nice_string(cls, string):
 
        first_regex = re.compile(r"([a-z][a-z]).*\1")
        second_regex = re.compile(r"([a-z]).\1")
 
        if not first_regex.search(string):
            return False
        if not second_regex.search(string):
            return False
        return True
 
        # # Process the input as a stream of characters
        # # First requirement:
        # #   - Break up the string into a list of 2-char substrings,
        # #   - As each pair is created, add it to a set
        # #   - If the set already has the substring, continue to the next requirement
        # #   - Else if we get to the end of the string, return False
        # n = 2
        # two_char_substring = [string[i:i+n] for i in range(0, len(string), n)]
        # unique_pairs = set([])
        # for pair in two_char_substring:
        #     print(pair)
        #     if pair in unique_pairs:
        #         print(f'Pair {pair} found in string')
        #         break
        #     else:
        #         unique_pairs.add(pair)
        # if (len(two_char_substring) == len(unique_pairs)):
        #     return False
 
        # print("passed first req")
        # # Second requirement:
        # #  - For each char in the string, compare it to the penultimate char
        # #  - if it matches the penultimate char, requirement is satisfied
        # meets_second_req = False
        # penultimate_char = string[0]
        # prev_char = string[1]
        # for c in string[2:]:
        #     if c == penultimate_char:
        #         meets_second_req = True
        #         break
        #     else:
        #         penultimate_char = prev_char
        #         prev_char = c
        # if not meets_second_req:
        #     return False
    
        # return True
 
 
 
def main():
    path = os.path.join(os.path.dirname(__file__), "input")
    with open(path) as f:
        puzzle_input = f.read()
 
    print("Part 1:", Part1.solve(puzzle_input))
    print("Part 2:", Part2.solve(puzzle_input))
 
    # print("Part 1:", part1(puzzle_input)) # 238
    # print("Part 2:", part2(puzzle_input))
 
 
if __name__ == '__main__':
    main()

day07_test.py

from day04 import part1
 
class TestPuzzle1(object):
 
   def test_example_1(self):
     input = "abcdef"
     expected = 609043
     assert part1(input) == expected
 
   def test_example_2(self):
     input = "pqrstuv"
     expected = 1048970
     assert part1(input) == expected