【LeetCode 234_連結串列】Palindrome Linked List

QingLiXueShi發表於2015-07-25
LeetCode

 1 ListNode* ReverseList(ListNode *p) {
 2     if (p == NULL || p->next == NULL)
 3         return p;
 4 
 5     ListNode *pre = NULL;
 6     ListNode *next = p->next;
 7     while (p) {
 8         p->next = pre;
 9         pre = p;
10         p = next;
11         next = p ? p->next : NULL;
12     }
13     return pre;
14 }
15 
16 bool isPalindrome(ListNode* head) {
17     if (head == NULL || head->next == NULL)
18         return true;
19     ListNode *slow = head, *fast = head;
20     while (fast->next && fast->next->next) {
21         slow = slow->next;
22         fast = fast->next->next;
23     }
24     slow->next = ReverseList(slow->next);
25     slow = slow->next;
26 
27     while (slow) {
28         if (slow->val != head->val)
29             return false;
30         slow = slow->next;
31         head = head->next;
32     }
33     return true;
34 }

 

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