82. Remove Duplicates from Sorted List II

pre.next设置成下一个数字的第一个 下一个数字进行循环 循环到相同的数字的最后一个 要是pre.next = node1 说明只有unique pre=pre.next, 否则说明不unique pre.next设置成下一个数字的第一个 就是pre.next = node1.next

https://leetcode.com/problems/remove-duplicates-from-sorted-list-ii/discuss/28335/My-accepted-Java-code?page=1

 

 

 

 

class Solution {
    public ListNode deleteDuplicates(ListNode head) {
        if(head == null || head.next == null) return head;
        ListNode node1 = head;
        ListNode dummy = new ListNode(0);
        dummy.next = head;
        ListNode pre = dummy;
        while(node1 != null) {
            if(node1.next != null && node1.val == node1.next.val){
                node1 = node1.next;
            }else {
                if(pre.next == node1) {
                    pre = pre.next;
                }else {
                    pre.next = node1.next;
                }
                node1 = node1.next;
            }
        }
        return dummy.next;  
    }
}