21.03.09 LeetCode83. 删除排序链表中的重复元素

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode() {}
 *     ListNode(int val) { this.val = val; }
 *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
 * }
 */
class Solution {
    public ListNode deleteDuplicates(ListNode head) {
        if(head==null)
            return null;
        ListNode pre = head;
        ListNode cur = pre.next;
        while(cur!=null)
        {
            //这里需要执行从pre为头，cur一直往下对比直到无重复元素为止
            while(cur!=null && cur.val==pre.val)
                cur = cur.next;
            //直到cur移动到不等于pre值的位置，与pre进行连接
            pre.next = cur;
            pre = pre.next;
        }
        return head;
    }
}