技術標籤：leetcode連結串列演算法leetcode

234. Palindrome Linked List

/**
 * 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) {
        if(!head ||
 
 !head->next) return true;
        ListNode *newHead = new ListNode(0), *p, *q, *t;
        newHead->next = head;
        int len = 0, cnt = 1;
        for(p = head; p; p = p->next) len++;
        for(p = head; cnt < len/2; cnt++) {
            q = p->next;
            p->next = q->
 
next;
            q->next = newHead->next;
            newHead->next = q;
        }
        if(len % 2) q = p->next->next; 
        else q = p->next;
        p = newHead->next;
        for(cnt = 0; cnt < len/2; p = p->next, q = q->next, cnt++) {
            if(p->val !=
 
 q->val) return false;
        }
        return true;
    }
};