删除链表的重复元素(二)

要求

删除链表中的重复元素,例如1->1->1->2->3->3->4->4->5，返回2->5

代码实现

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#include <iostream>
using namespace std;

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;
        }else{
            ListNode* newHead = new ListNode(0);
            newHead->next = head;
            ListNode* pre = newHead;
            ListNode* p = pre->next;
            ListNode* next = NULL;
            while (p!=NULL&&p->next!=NULL) {
                next = p->next;
                if (p->val==next->val) {
                    while (next!=NULL&&next->val==p->val) {
                        next = next->next;
                    }
                    pre->next = next;
                    p = next;
                }else{
                    pre = pre->next;
                    p =  p->next;
                }
            }
            return newHead->next;

        }
    }
};
int main(int argc, const char * argv[]) {
    return 0;
}

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