#!/usr/bin/env python import itertools import sys from typing import Iterator, List, Optional 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 def complete_line(input: str) -> str: chunks: List[str] = [] start_to_end = { "(": ")", "[": "]", "{": "}", "<": ">", } for c in input: # Is it a chunk beginning if c in start_to_end: chunks.append(c) continue # Otherwise we must match the last open chunk assert start_to_end[chunks.pop()] == c # Sanity check return "".join(reversed(list(start_to_end[c] for c in chunks))) def score_completion(completion: str) -> int: char_score = { ")": 1, "]": 2, "}": 3, ">": 4, } score = 0 for c in completion: score *= 5 score += char_score[c] return score def score_completions(completions: Iterator[str]) -> int: scores = sorted(map(score_completion, completions)) return scores[len(scores) // 2] incomplete_lines = filter(lambda line: find_illegal_char(line) is None, input) completions = map(complete_line, incomplete_lines) return score_completions(completions) def main() -> None: input = [line.strip() for line in sys.stdin.readlines()] print(solve(input)) if __name__ == "__main__": main()