Source: Rope Bridge
Part 1
Simulate two connected links such that whenever the first link (head) moves, the tail moves to follow according to the following rules:
- If the tail is at the same location as head, don’t move
- If the tail is adjacent to the head (orthogonal or diagonal), don’t move
- If the tail is in the same row/column as the head, move one directly towards it orthogonally
- If the tail is in neither the same row nor column, move one towards diagonally
Count how many unique spaces are visited by the tail of the link.