aoc-2021/10.py

from util import get_input

input = get_input("10.input")

corresp = {
        ')': '(',
        ']': '[',
        '}': '{',
        '>': '<',
        }

def find_illegal(line):
    stack = []

    for c in line:
        if c in ['(', '[', '{', '<']:
            stack.append(c)
        else:
            if len(stack) == 0:
                return None
            if stack[-1] != corresp[c]:
                return c
            else:
                stack.pop()

    return stack

points = {
        ')': 3,
        ']': 57,
        '}': 1197,
        '>': 25137,
        }

results = [find_illegal(line) for line in input]

print("Part 1:", sum([points.get(c, 0) for c in results if type(c) == str]))

remaining = [stack for stack in results if type(stack) == list]

points = {
        '(': 1,
        '[': 2,
        '{': 3,
        '<': 4,
        }

def get_score(stack):
    sum = 0
    while len(stack) > 0:
        sum *= 5
        sum += points[stack.pop()]
    return sum

scores = [get_score(s) for s in remaining]

scores.sort()

print("Part 2:", scores[int(len(scores) / 2)])