83. Remove Duplicates from Sorted List

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.

总算自己做出来一道了，虽然只是一道easy, 但好像连续几道都是看的答案。这道题确实简单吧，思路都很直接，注意一下循环条件就好了。（我是报错NullPointerException后自己加的curt.next != null && curt.val == curt.next.val. 入股不加上curt.next != null, 那么curt.next.val就会报空指针。）

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode deleteDuplicates(ListNode head) {
        if (head == null){
            return head;
        }
        ListNode dummy = new ListNode(0);
        dummy.next = head;
        ListNode curt = head;
        while (curt != null && curt.next != null){
            while (curt.next != null && curt.val == curt.next.val){
                curt.next = curt.next.next;
            }
            curt = curt.next;
        }
        return dummy.next;
    }
}