AoC 2020: day19

Signed-off-by: Ettore Dreucci <ettore.dreucci@gmail.com>

2020-python/solutions/day_19.py

@@ -0,0 +1,153 @@
+"""AOC 2020 Day 19"""
+
+import pathlib
+import time
+import re
+
+TEST_INPUT = """0: 4 1 5
+1: 2 3 | 3 2
+2: 4 4 | 5 5
+3: 4 5 | 5 4
+4: "a"
+5: "b"
+
+ababbb
+bababa
+abbbab
+aaabbb
+aaaabbb"""
+
+TEST_INPUT_2 = """42: 9 14 | 10 1
+9: 14 27 | 1 26
+10: 23 14 | 28 1
+1: "a"
+11: 42 31
+5: 1 14 | 15 1
+19: 14 1 | 14 14
+12: 24 14 | 19 1
+16: 15 1 | 14 14
+31: 14 17 | 1 13
+6: 14 14 | 1 14
+2: 1 24 | 14 4
+0: 8 11
+13: 14 3 | 1 12
+15: 1 | 14
+17: 14 2 | 1 7
+23: 25 1 | 22 14
+28: 16 1
+4: 1 1
+20: 14 14 | 1 15
+3: 5 14 | 16 1
+27: 1 6 | 14 18
+14: "b"
+21: 14 1 | 1 14
+25: 1 1 | 1 14
+22: 14 14
+8: 42
+26: 14 22 | 1 20
+18: 15 15
+7: 14 5 | 1 21
+24: 14 1
+
+abbbbbabbbaaaababbaabbbbabababbbabbbbbbabaaaa
+bbabbbbaabaabba
+babbbbaabbbbbabbbbbbaabaaabaaa
+aaabbbbbbaaaabaababaabababbabaaabbababababaaa
+bbbbbbbaaaabbbbaaabbabaaa
+bbbababbbbaaaaaaaabbababaaababaabab
+ababaaaaaabaaab
+ababaaaaabbbaba
+baabbaaaabbaaaababbaababb
+abbbbabbbbaaaababbbbbbaaaababb
+aaaaabbaabaaaaababaa
+aaaabbaaaabbaaa
+aaaabbaabbaaaaaaabbbabbbaaabbaabaaa
+babaaabbbaaabaababbaabababaaab
+aabbbbbaabbbaaaaaabbbbbababaaaaabbaaabba"""
+
+def read_input(input_path: str) -> str:
+    """take input file path and return a str with the file's content"""
+    with open(input_path, 'r') as input_file:
+        input_data = input_file.read().strip()
+        return input_data
+
+def extract(input_data: str) -> tuple:
+    """take input data and return the appropriate data structure"""
+    rules = dict()
+    messages = list()
+    rules_input, messages_input = input_data.split('\n\n')[0:2]
+
+    for rule_input in rules_input.split('\n'):
+        rule_id, rule = rule_input.split(': ')
+        rules[rule_id] = rule
+
+    messages = messages_input.split('\n')
+
+    return rules, messages
+
+def get_regxp(rule_num: str, rules: dict):
+    rule = rules[rule_num]
+    if re.fullmatch('"."', rule):
+        return rule[1]
+    rule_parts = rule.split(' | ')
+    or_rules = []
+    for part in rule_parts:
+        numbers = part.split(' ')
+        or_rules.append(''.join(get_regxp(n, rules) for n in numbers))
+
+    return f"(?:{'|'.join(or_rules)})"
+
+def get_regxp_upd(rule_num: str, rules: dict):
+    if rule_num == '8':
+        return f"{get_regxp_upd('42', rules)}+"
+    elif rule_num == '11':
+        rule_11 = (f"{get_regxp_upd('42', rules)}{{{n}}}{get_regxp_upd('31', rules)}{{{n}}}" for n in range(1, 22))
+        return f"(?:{'|'.join(rule_11)})"
+    
+    rule = rules[rule_num]
+    if re.fullmatch('"."', rule):
+        return rule[1]
+    rule_parts = rule.split(' | ')
+    or_rules = []
+    for part in rule_parts:
+        numbers = part.split(' ')
+        or_rules.append(''.join(get_regxp_upd(n, rules) for n in numbers))
+
+    return f"(?:{'|'.join(or_rules)})"
+
+def part1(entries: tuple) -> int:
+    """part1 solver"""
+    rules, messages = entries
+    regxp_0 = re.compile(get_regxp('0', rules))
+    return sum(regxp_0.fullmatch(x) is not None for x in messages)
+
+def part2(entries: tuple) -> int:
+    """part2 solver"""
+    rules, messages = entries
+    regxp_0 = re.compile(get_regxp_upd('0', rules))
+    return sum(regxp_0.fullmatch(x) is not None for x in messages)
+
+def test_input_day_19():
+    """pytest testing function"""
+    entries = extract(TEST_INPUT)
+    assert part1(entries) == 2
+    entries = extract(TEST_INPUT_2)
+    assert part2(entries) == 12
+
+def test_bench_day_19(benchmark):
+    """pytest-benchmark function"""
+    benchmark(main)
+
+def main():
+    """main function"""
+    input_path = str(pathlib.Path(__file__).resolve().parent.parent) + "/inputs/" + str(pathlib.Path(__file__).stem)
+    start_time = time.time()
+    input_data = read_input(input_path)
+    entries = extract(input_data)
+    print("Part 1: %d" % part1(entries))
+    print("Part 2: %d" % part2(entries))
+    end_time = time.time()
+    print("Execution time: %f" % (end_time-start_time))
+
+if __name__ == "__main__":
+    main()