【原创】leetCodeOj ---Remove Duplicates from Sorted List II 解题报告

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原题地址：

https://oj.leetcode.com/problems/remove-duplicates-from-sorted-list-ii/

题目内容：

Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.

For example,
Given 1->2->3->3->4->4->5, return 1->2->5.
Given 1->1->1->2->3, return 2->3.

方法：

递归做非常直观。

判断当前节点的值是否等于下一个节点的值，若不等，直接递归调用下一个节点；

若相等，则找到下一个不和当前节点相等的节点，并将其更新为当前节点，同时递归调用该节点。

全部代码：

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