leetcode 82. 删除排序链表中的重复元素 II(Remove Duplicates from Sorted List II)

目录

• 题目描述：
• 示例 1:
• 示例 2:
• 解法：

题目描述：

给定一个排序链表，删除所有含有重复数字的节点，只保留原始链表中 没有重复出现 的数字。

示例 1:

输入: 1->2->3->3->4->4->5
输出: 1->2->5

示例 2:

输入: 1->1->1->2->3
输出: 2->3

---

解法：

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* deleteDuplicates(ListNode* head) {
        ListNode* _head = NULL;
        ListNode* nxt = NULL;
        if(head == NULL){
            return head;
        }
        int pre = head->val;
        ListNode* cur = head->next;
        bool repeated = false;
        while(cur != NULL){
            if(cur->val != pre){
                if(repeated == false){
                    if(_head == NULL){
                        _head = new ListNode(pre);
                        nxt = _head;
                    }else{
                        nxt->next = new ListNode(pre);
                        nxt = nxt->next;
                    }
                }
                repeated = false;
                pre = cur->val;
            }else{
                repeated = true;
            }
            cur = cur->next;
        }
        if(repeated == false){
            if(_head == NULL){
                _head = new ListNode(pre);
            }else{
                nxt->next = new ListNode(pre);    
            }
        }
        return _head;
    }
};