How do you remove the Nth node from the end of a linked list?

Short answer: Two pointers with a gap of n. Advance fast n steps, then move both until fast hits the end; slow.next is the node to delete. One pass, O(1) space.

Edge cases to mention

• Remove head (n == length)
• Single node list
• n = 1 (remove tail)

Use a dummy head so deleting the real head is uniform.