LeetCode | Remove Duplicates from Sorted List

题目

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

.
分析
可以双指针遍历一下删一段，也可以单指针遍历，一次删一个。这里是双指针的写法。

代码

public class RemoveDuplicatesFromSortedList {
public ListNode deleteDuplicates(ListNode head) {
if (head == null) {
return head;
}
ListNode p = head;
ListNode q = head.next;
while (q != null) {
if (q.val != p.val) {
p.next = q;
p = q;
}
q = q.next;
}
p.next = q;
return head;
}
}