Cinte's Leetcode Record
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83. 删除排序链表中的重复元素

Posted on Edited on In Disqus:
Symbols count in article: 1.3k Reading time ≈ 1 mins.

83. 删除排序链表中的重复元素

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/**
 * 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* pt = head;
        ListNode* pre = new ListNode(-101);
        pre->next = head;
        while(pt)
        {
            if(pre->val == pt->val)
            {
                while(pt && pre->val == pt->val)
                {
                    auto tmp = pt;
                    pt = pt->next;
                    delete tmp;
                }
                pre->next = pt;
            }
            if(!pt)
                break;
            pre = pt;
            pt = pt->next;
        }
        return head;
    }
};

改

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/**
 * 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)
            return nullptr;
        ListNode* pt = head;
        while(pt->next)
        {
            if(pt->val == pt->next->val)
            {
                auto tmp = pt->next;
                pt->next = pt->next->next;
                delete tmp;
            }else
                pt = pt->next;
        }
        return head;
    }
};