Tricks

Slow-Fast pointers

We can use 2 pointers to traverse a linked list. That can reduce complexity.

The interval between 2 pointers is important.

• fixed interval

  For example, Remove Nth Node From End of List.

  We set the interval as n. When fast pointer is None, we return the slow pointer.

  slow pointer should be initialized as a dummy node pointed to the head of the list.

• varied interval

  For example, Middle of the Linked List.

  The step of the fast pointer should be twice as the slow one.