【11_83】Remove Duplicates from Sorted List

这道题本质上不难，难的是细节处理，容易出错。

第一遍写的代码越改越大，越臃肿，此时，不如推倒重写，果然，第二次一遍过。

 

Remove Duplicates from Sorted List

My Submissions

Question

Total Accepted: 90731 Total Submissions: 255705 Difficulty: Easy

 

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.

 

下面是Discuss里面的好代码：只有三行！！！

Java写法

public ListNode deleteDuplicates(ListNode head) {
        if(head == null || head.next == null)return head;
        head.next = deleteDuplicates(head.next);
        return head.val == head.next.val ? head.next : head;
}

 

另一个好代码，和我的思想差不多，不过更简洁：

public class Solution {
    public ListNode deleteDuplicates(ListNode head) {
        if (head == 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;
    }
}

 

 然后是我自己写的：

C语言

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     struct ListNode *next;
 * };
 */
struct ListNode* deleteDuplicates(struct ListNode* head) {
    if (head == NULL)
        return NULL;
    if (head->next == NULL)
        return head;
        
    struct ListNode* p = head;
    struct ListNode* q = p->next;
    while(p->next != NULL)  {
        if(p->val == p->next->val)  {
            p->next = p->next->next;
        }
        else if(p->next != NULL)
            p = p->next;
    }
    
    return head;
}