Remove Duplicates from Sorted List II

题目大意：给定一个链表，要求将相邻重复的节点给删除

解题思路：最开始找到一个pre节点，这个pre节点表示从开始到pre这个节点，链表已经去重

那么这个节点表示上一次不重复的节点

/**
 * 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) {
        if(head == NULL || head->next == NULL) {
            return head;
        }
        ListNode *pre = NULL, *newHead = NULL;
        ListNode *cur = head;
        bool find = false;
        while(cur != NULL) {
            ListNode *tmp = cur;
            find = false;
            cur = cur->next;
            while(cur != NULL && tmp->val == cur->val) {
                cur = cur->next;
                find = true;
            }
            if(!find) {
                newHead = pre = tmp;
                break;
            }
        }

      
        while(cur != NULL) {
            while(cur->next != NULL && pre->next->val == cur->next->val) {
                cur = cur->next;
            }
            if(pre->next == cur) {
                pre = cur;
            } else {
                pre->next = cur->next;
            }
            cur = cur->next;
        }
        return newHead;
    }
};