adventofcode2020/day3a.py

def main():
    with open("input3.txt") as file:
        lines = file.readlines()
    grid = [list(line.strip()) for line in lines]
    print(grid[0])
    wrap = len(grid[0])
    coords = [0,0] # x, y - across, down
    trees = 0
    while coords[1] < len(grid):
        print(coords)
        if grid[coords[1]][coords[0]] == "#":
            trees += 1
        coords[0] = coords[0] + 3
        coords[1] = coords[1] + 1
        if coords[0] >= wrap:
            coords[0] = coords[0] - wrap
    print(f"It's been a long toboggan trip, and I encountered {trees} trees.")


if __name__ == "__main__":
    main()