day9-simple-part1-working2.py

# open the input file and read the lines
with open("input.txt") as f:
    lines = f.readlines()

# initialize the head and tail at the same position
head = (0, 0)
tail = (0, 0)

# parse the list of movements for the head from the input file
movements = [line.strip() for line in lines]

# create a set to store the positions visited by the tail
tail_positions = set()

# iterate over the movements and update the position of the head and tail
for move in movements:
    direction, steps = move.split()
    steps = int(steps)
    
    for i in range(steps):
        if direction == "R":
            head = (head[0] + 1, head[1])
        elif direction == "L":
            head = (head[0] - 1, head[1])
        elif direction == "U":
            head = (head[0], head[1] + 1)
        elif direction == "D":
            head = (head[0], head[1] - 1)
        
        # check if the tail is still adjacent to the head, and move it if necessary
        if abs(head[0] - tail[0]) > 1 or abs(head[1] - tail[1]) > 1:
            if direction == "R":
                tail = (head[0] - 1, head[1])
            elif direction == "L":
                tail = (head[0] + 1, head[1])
            elif direction == "U":
                tail = (head[0], head[1] - 1)
            elif direction == "D":
                tail = (head[0], head[1] + 1)
        
        # add the position of the tail to the set of tail positions
        tail_positions.add(tail)
        
# print the final positions of the head and tail, and the number of unique positions visited by the tail
print("Final position of the head:", head)
print("Final position of the tail:", tail)
print("Number of unique positions visited by the tail:", len(tail_positions))