[LeetCode][链表]Remove Duplicates from Sorted List

题目描述：

Given a sorted linked list, delete all duplicates such that each element appear only once.

For example,

Given

1->1->2

, return

1->2

.

Given

1->1->2->3->3

, return

1->2->3

.

思路：

前提：排好序的链表

过程：和数组的去重思路是一样的，如果相邻的两个结点值相同，则next指针指向它的下下位结点，差别在于链表中需要多存储一个结点实现两个结点的比较和移动

代码实现：

/**
* Definition for singly-linked list.
* public class ListNode {
*     int val;
*     ListNode next;
*     ListNode(int x) { val = x; }
* }
*/
public class Solution {
public ListNode deleteDuplicates(ListNode head) {
if(head == null||head.next == null){
return head;
}

ListNode prev = head;
ListNode p = head.next;

while(p != null){
if(prev.val == p.val){
prev.next = p.next;
p = p.next;
}else{
prev = p;
p = p.next;
}
}

return head;
}
}