diff --git a/2021/d10/ex1/ex1.py b/2021/d10/ex1/ex1.py new file mode 100755 index 0000000..4667d43 --- /dev/null +++ b/2021/d10/ex1/ex1.py @@ -0,0 +1,51 @@ +#!/usr/bin/env python + +import itertools +import sys +from typing import List, Optional, cast + + +def solve(input: List[str]) -> int: + def find_illegal_char(input: str) -> Optional[int]: + chunks: List[str] = [] + ends_to_start = { + ")": "(", + "]": "[", + "}": "{", + ">": "<", + } + + for i, c in enumerate(input): + # Is it a chunk beginning + if c not in ends_to_start: + chunks.append(c) + continue + # Is it matching the last element on the chunk stack + current = chunks.pop() + # If not, corruption has been found + if ends_to_start[c] != current: + return i + + return None + + score = { + ")": 3, + "]": 57, + "}": 1197, + ">": 25137, + } + + return sum( + score[line[cast(int, find_illegal_char(line))]] + for line in input + if find_illegal_char(line) is not None + ) + + +def main() -> None: + input = [line.strip() for line in sys.stdin.readlines()] + print(solve(input)) + + +if __name__ == "__main__": + main()