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

.

思路：

package list;

public class RemoveDuplicatesFromSortedList {

public ListNode deleteDuplicates(ListNode head) {
ListNode p = head;
ListNode start = head;
while (head != null && head.next != null) {
ListNode headNext = head.next;
if (head.next.val != head.val) {
start = head.next;
} else {
start.next = head.next.next;
}

head = headNext;
}
return p;
}

public static void main(String[] args) {
// TODO Auto-generated method stub
ListNode a1 = new ListNode(1);
ListNode a2 = new ListNode(1);
ListNode a3 = new ListNode(1);
ListNode a4 = new ListNode(1);
ListNode a5 = new ListNode(1);
a1.next = a2;
a2.next = a3;
a3.next = a4;
a4.next = a5;
a5.next = null;
RemoveDuplicatesFromSortedList r = new RemoveDuplicatesFromSortedList();
ListNode head = r.deleteDuplicates(a1);
while (head != null) {
System.out.println(head.val);
head = head.next;
}
}

}