Leetcode 83. Remove Duplicates from Sorted List

Given a sorted linked list, delete all duplicates such that each element appear only once.

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

水題  注意邊界和要判斷下一個節點

/**
 * 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)
        {
         return NULL;   
        }
        if(head->next == NULL){
            return head;
        }
        ListNode* temp = head;
        while(temp->next!=NULL){
            if(temp->next->val == temp->val&&temp->next->next!=NULL){
                temp->next = temp->next->next;
            }else if(temp->next->val == temp->val&&temp->next->next==NULL){
                temp->next = NULL;
            }else{
                temp = temp->next;
            }
            
        }
    return head;
    }
};