Leetcode 234 Palindrome Linked List 链表

判断链表是否是回文。

我直接将链表的一半进行倒置，然后将两半的链表进行比较

 /**
  * 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) {
         int ln = , i = ;
         ListNode* rhead = NULL;
         ListNode* now, *rnow;
         for(now = head; now; now = now->next, ++ln);
         for(now = head; i < ln / ; ++i){
             ListNode* tnow = now;
             now = now->next;
             tnow->next = rhead;
             rhead = tnow;
         }
         if(ln %  == ){
             now = now->next;
         }
         for(rnow = rhead; now && rnow; rnow = rnow->next, now = now->next){
             if(rnow->val != now->val) return false;
         }
         return true;
     }
 };