Find middle with unknown size.

• find word in sorted dictionary with unknown size. slow = 0, fast = 1. (index)

• find middle node of a linkedlist. slow = head, fast = head.next

Convert structure

1) 找规律，一些operation组合

• odd even\/ palindrome

  • reverse \/ merge \/ stack..

2) Recursion

How to draw linkedlist ?

-> draw null as tail

How to view a linkedlist?

a pointer points to head of list. however, this is a list!!!