Cinte's Leetcode Record
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面试题 02.06. 回文链表

Posted on Edited on In Disqus:
Symbols count in article: 648 Reading time ≈ 1 mins.

面试题 02.06. 回文链表

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/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    bool isPalindrome(ListNode* head) {
        ListNode *walker = head, *runner = head;
        ListNode* pre = nullptr;
        while(runner && runner->next)
        {
            runner = runner->next->next;
            auto next = walker->next;
            walker->next = pre;
            pre = walker;
            walker = next;
        }
        if(runner)
            walker = walker->next;
        while(pre && walker && pre->val == walker->val) {
            pre = pre->next;
            walker = walker->next;
        }
        return !(pre || walker);
    }
};