aoc-2021/5.py

from util import get_input
from collections import namedtuple
from more_itertools import flatten

input = get_input("5.input")

Point = namedtuple("Point", ['x', 'y'])

input = [[Point(int(pair.split(",")[0]), int(pair.split(",")[1])) for pair in line.split(" -> ")] for line in input]

maxx = max([p.x for p in flatten(input)])
maxy = max([p.y for p in flatten(input)])
board = [[0 for _ in range(maxy + 1)] for _ in range(maxx + 1)]

def sign(n):
    return 0 if n == 0 else (1 if n > 0 else -1)

for line in input:
    dx = sign(line[1].x - line[0].x)
    dy = sign(line[1].y - line[0].y)
    x = line[0].x
    y = line[0].y
    while x != line[1].x or y != line[1].y:
        board[x][y] += 1
        x += dx
        y += dy
    board[x][y] += 1

print(sum([1 for num in flatten(board) if num > 1]))