from fileio import open
let f = open('test/day3.in')
let lines = f.read().split('\n')[:-1]

def count_trees(lines, x_off, y_off):
    let modulo = len(lines[0])
    let x, y, trees = 0, 0, 0
    while y < len(lines):
        if lines[y][x % modulo] == '#':
            trees += 1
        x += x_off
        y += y_off
    return trees

print("part 1:", count_trees(lines, 3, 1))
print("part 2:", count_trees(lines, 1, 1) * count_trees(lines, 3, 1) * count_trees(lines, 5, 1) * count_trees(lines, 7, 1) * count_trees(lines, 1, 2))