Remove Duplicates from Sorted List

文章目录

1. 1. Remove Duplicates from Sorted List
   1. 1.1. 题目
   2. 1.2. 思路
   3. 1.3. 解题

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.

思路

cur表示当前结点，cur->next表示下一结点。若cur->val等于cur->next->val,则删除cur->next这一结点,按下述操作cur->next=cur->next->next。否则cur=cur->next。

解题

c++版

/** * Definition for singly-linked list. * struct ListNode { *     int val; *     ListNode *next; *     ListNode(int x) : val(x), next(NULL) {} * }; */
 * 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 NULL;
        ListNode *cur=head;
        while(cur->next){
            if(cur->next->val==cur->val)
                cur->next=cur->next->next;
            else
                cur=cur->next;
        }
        return head;
    }
};

python版

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution:
    # @param head, a ListNode
    # @return a ListNode
    def deleteDuplicates(self, head):
        dummy=ListNode(-1)
        dummy.next=head
        cur=dummy.next
        while cur and cur.next:
            if cur.val==cur.next.val:
                cur.next=cur.next.next
            else:
                cur=cur.next
        return dummy.next