LeetCode 83. Remove Duplicates from Sorted List

原题链接在这里：https://leetcode.com/problems/remove-duplicates-from-sorted-list/

题目：

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.

题解：

Time Complexity: O(n), n是list长度. Space: O(1).

AC Java:

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
public class Solution {
    public ListNode deleteDuplicates(ListNode head) {
        if(head == null || head.next == null){
            return head;
        }
        ListNode cur = head;
        while(cur.next != null){
            if(cur.val == cur.next.val){
                cur.next = cur.next.next;
            }else{
                cur = cur.next;
            }
        }
        return head;
    }
}

AC C++:

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */
class Solution {
public:
    ListNode* deleteDuplicates(ListNode* head) {
        if(!head || !head->next){
            return head;
        }

        ListNode* it = head;
        while(it->next){
            if(it->val == it->next->val){
                it->next = it->next->next;
            }else{
                it = it->next;
            }
        }

        return head;
    }
};

跟上Remove Duplicates from Sorted List II, Remove Duplicates from Sorted Array.