leetcode

Solution to some Leetcode problems written in C++

git clone git://git.dimitrijedobrota.com/leetcode.git

0234.cpp (878B)

0 class Solution { 1 public: 2 ListNode *invert(ListNode *head) { 3 ListNode *p, *q, *r; 4 5 p = head; 6 q = nullptr; 7 while (p) { 8 r = q; 9 q = p; 10 p = p->next; 11 q->next = r; 12 } 13 return q; 14 } 15 16 ListNode *first_half_end(ListNode *head) { 17 ListNode *fast, *slow; 18 fast = slow = head; 19 while (fast->next && fast->next->next) { 20 fast = fast->next->next; 21 slow = slow->next; 22 } 23 return slow; 24 } 25 26 bool isPalindrome(ListNode *head) { 27 if (!head || !head->next) return true; 28 29 ListNode *fhe = first_half_end(head); 30 ListNode *shs = invert(fhe->next); 31 32 for (ListNode *p = head, *tmp = shs; tmp; p = p->next, tmp = tmp->next) 33 if (p->val != tmp->val) return false; 34 35 return true; 36 } 37 };