Leetcode 61. Rotate List

Given a list, rotate the list to the right by K -places, where K is non-negative.

For example:
Given 1->2->3->4->5->NULL and k = 2 ,
Return 4->5->1->2->3->NULL .

Analysis:

1. Compute the length of list m
2. partition list into the small list, notice that it moves exactly to the end of the list, and the next is null!!
Before list is List1, after list was list2, set last node in list1 List1.next = null
3. Concatenate the tail of the list to the head of one list

Java Code

20160601

/*** Definition for singly-linked list. * public class ListNode {* int val; * ListNode Next; * ListNode (int X) {val = x;}}*/ Public classSolution { PublicListNode Rotateright (ListNode head,intk) {//1. Compute the length of list m//2. Partition list into the small list,//before list is List1, after list was list2, set last node in list1 list1.next = null//3. Concatenate the tail of the list to the head of one list//Base Case        if(Head = =NULL|| Head.next = =NULL|| K = = 0) {            returnHead; }        intm =GetLength (head); intMovestep = m-k% m-1; ListNode cur=Head; ListNode One=Head; ListNode=NULL;  while(Movestep > 0) {cur=Cur.next; Movestep--; }        if(Cur.next = =NULL) {//move to the end of the linked list, no rotate            returnHead; }=Cur.next; Cur.next=NULL; ListNode Twohead=both ;  while(Two.next! =NULL) {=Two.next; } Two.next=One ; returnTwohead; }        Private intGetLength (ListNode head) {intLen = 0;  while(Head! =NULL) {Head=Head.next; Len++; }        returnLen; }}

Leetcode 61. Rotate List