leetcode 83. Remove Duplicates from Sorted List

最新推荐文章于 2025-12-04 16:02:12 发布

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本文介绍了一种高效算法，用于删除单链表中所有重复出现的元素，通过遍历链表并比较节点值来实现。该算法保持了链表原有的顺序，并在删除重复项后返回更新后的链表。

/**
 * 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 == NULL) return NULL;
        ListNode * here = head->next,*h = head;
        while(here != NULL){
            if(head->val == here->val){
                here = here->next;
            }
            else {
                head->next = here;
                head = head->next;
                here - here->next;
            }
        }
        head->next =NULL;
        return h;
    }
};

快一点的

/**
 * 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 == NULL) return NULL;
        ListNode * here = head->next,*h = head;
        int n = head->val;
        while(here != NULL){
            if(here->val == n){
                here = here->next;
            }
            else {
                h->next=here;
                h = h->next;
                n=here->val;
                here=here->next;
            }
        }
        h->next=NULL;
        return head;
    }
};