[Leetcode]Remove Duplicates from Sorted List II

Remove Duplicates from Sorted List II
Total Accepted: 58686 Total Submissions: 228299 Difficulty: Medium

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.

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这道题其实是没啥的，但是让我更深刻的认识了什么叫做”短路求值“！

/**
 * 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)   return nullptr;
        ListNode* h = new ListNode(-1);
        h->next = head;
        ListNode* p = head;
        ListNode* prev = h;
        while(p != nullptr && p->next){ // if u write "p->next" before "p != nullptr",u will get "Runtime Error" in [1,1];
            ListNode* Next = p->next;
            if(p->val != Next->val){
                prev = p;
                p = Next;
                continue;
            }
            while(Next != nullptr && p->val == Next->val){//plz see 17th-lines
                Next = Next->next;
            }
            prev->next = Next;
            p = Next;
        }
        return h->next;
    }
};