leetcode刷题（108）——83. 删除排序链表中的重复元素

输入: 1->1->2
输出: 1->2

输入: 1->1->2->3->3
输出: 1->2->3

class Solution {
    public ListNode deleteDuplicates(ListNode head) {
    if (head == null) return null;
    ListNode slow = head, fast = head;
    while (fast != null) {
        if (fast.val != slow.val)  {
            // nums[slow] = nums[fast];
            slow.next = fast;
            // slow++;
            slow = slow.next;
        }
        // fast++
        fast = fast.next;
    }
    // 断开与后面重复元素的连接
    slow.next = null;
    return head;
    }
}