leetcode刷题系列----模式2（Datastructure 链表）- 83：Remove Duplicates from Sorted List 删除排序链表中的重复元素

leetcode刷题系列----模式2（Datastructure 链表）- 83：Remove Duplicates from Sorted List 删除排序链表中的重复元素

Tips

• 更多题解请见本系列目录
• 使用双指针解决。
• 链表类问题注意指针要随着迭代更新到next。

Python

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution:
    def deleteDuplicates(self, head: ListNode) -> ListNode:
        previous = head
        if not head: return head
        while(previous.next):
            current = previous.next
            if (previous.val==current.val): previous.next = current.next
            else: previous=previous.next
        return head

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) {
        ListNode* previous = head;
        ListNode* current = head;
        if(head==nullptr) return head;
        while(previous->next!=nullptr)
        {
            current = previous->next;
            if(current->val==previous->val) previous->next=current->next;
            else previous = previous->next;

        }
        return head;
    }
};

C#

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     public int val;
 *     public ListNode next;
 *     public ListNode(int val=0, ListNode next=null) {
 *         this.val = val;
 *         this.next = next;
 *     }
 * }
 */
public class Solution {
    public ListNode DeleteDuplicates(ListNode head) {
        ListNode previous = head;
        ListNode current = head;
        if(head==null) return head;
        while(previous.next!=null)
        {
            current = previous.next;
            if(current.val==previous.val) previous.next = current.next;
            else previous = previous.next;
        }
        return head;
    }
}

Java

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