EXAMPLE = """
R 4
U 4
L 3
D 1
R 4
D 1
L 5
R 2
"""

def clean(text: str) -> list[str]:
    return list(filter(lambda l: l.strip() != "", text.splitlines()))

def new_pos(h_pos, t_pos, dir):
    if dir == "R":
        new_h_pos = (h_pos[0] + 1, h_pos[1])
    elif dir == "U":
        new_h_pos = (h_pos[0], h_pos[1] + 1)
    elif dir == "L":
        new_h_pos = (h_pos[0] - 1, h_pos[1])
    elif dir == "D":
        new_h_pos = (h_pos[0], h_pos[1] - 1)
    elif dir == "NONE":
        new_h_pos = (h_pos[0], h_pos[1])
    else:
        raise Exception("Unexpected direction.")

    #  xxxxx
    #  x---x     
    #  x-O-x          
    #  x---x   
    #  xxxxx
    dx, dy = t_pos[0] - new_h_pos[0], t_pos[1] - new_h_pos[1]
    delta = {
        (-1, -1): (0, 0),
        (-1, 0): (0, 0),
        (-1, 1): (0, 0),
        (0, -1): (0, 0),
        (0, 0): (0, 0),
        (0, 1): (0, 0),
        (1, -1): (0, 0),
        (1, 0): (0, 0),
        (1, 1): (0, 0),
        (-2, 2): (1, -1),
        (-2, 1): (1, -1),
        (-2, 0): (1, 0),
        (-2, -1): (1, 1),
        (-2, -2): (1, 1),
        (2, 2): (-1, -1),
        (2, 1): (-1, -1),
        (2, 0): (-1, 0),
        (2, -1): (-1, 1),
        (2, -2): (-1, 1),
        (-1, 2): (1, -1),
        (-1, -2): (1, 1),
        (0, 2): (0, -1),
        (0, -2): (0, 1),
        (1, 2): (-1, -1),
        (1, -2): (-1, 1),
    }
    dx_, dy_ = delta[(dx, dy)]
    new_t_pos = t_pos[0] + dx_, t_pos[1] + dy_
    # print(f"{h_pos=} {t_pos=} {dir=}")
    # print(f"{new_h_pos=} {dx=} {dy=}")
    # print(f"{new_t_pos=}")
    # print("----")
    return new_t_pos, new_h_pos

def solve(lines: list[str]):
    pos = set()
    h_pos = (0, 0)
    t_pos = (0, 0)
    pos.add(t_pos)
    for i in range(len(lines)):
        dir, amount = lines[i].split()
        for _ in range(int(amount)):
            t_pos, h_pos = new_pos(h_pos, t_pos, dir)
            pos.add(t_pos)
    # 44:00
    return len(pos)

EXAMPLE2 = """
R 5
U 8
L 8
D 3
R 17
D 10
L 25
U 20
"""

def solve2(lines: list[str]):
    vis = set()
    poss = [(0, 0) for _ in range(10)]
    vis.add((0, 0))
    for i in range(len(lines)):
        dir, amount = lines[i].split()
        for _ in range(int(amount)):
            for i in range(len(poss) - 1):
                h_pos = poss[i]
                t_pos = poss[i + 1]
                if i == 0:
                    t_pos, h_pos = new_pos(h_pos, t_pos, dir)
                else:
                    t_pos, h_pos = new_pos(h_pos, t_pos, "NONE")
                poss[i] = h_pos
                poss[i + 1] = t_pos
            vis.add(poss[-1])
    # 58:00
    return len(vis)

def main():
    example = clean(EXAMPLE)
    print("Example  1:", solve(example))

    data = clean(open("i9.txt").read())
    print("Solution 1:", solve(data))

    example = clean(EXAMPLE2)
    print("Example  2:", solve2(example))

    data = clean(open("i9.txt").read())
    print("Solution 2:", solve2(data))

if __name__ == "__main__":
    main()