Link list of sword finger offer question bank summary (III) (C language version)

The finger of the sword offer Question bank summary （ 3、 ... and ） Linked list of （C Language version ）

topic 24. Reverse a linked list

• Title Description ： Reverse a linked list
  Given the head node of a single linked list pHead( The header node has a value , For example, in the figure below , its val yes 1), The length is n, After reversing the linked list , Return the header of the new linked list .
  Data range ： 0≤n≤1000
  requirement ： Spatial complexity O(1)O(1) , Time complexity O(n)O(n) .
  For example, when entering a linked list {1,2,3} when , After reversal , The original linked list becomes {3,2,1}, So the corresponding output is {3,2,1}.

• Their thinking ： Using recursive methods .
  If the linked list only 2 Elements &#