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.

分析：和Remove Duplicated from Sorted Array类似。运行时间19ms

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

Runtime: 16ms

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