leetcode

Solution to some Leetcode problems written in C++

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

0143.cpp (980B)

0 class Solution { 1 ListNode *reverseList(ListNode *head) { 2 ListNode *p, *q, *r; 3 4 p = head, q = nullptr; 5 while (p) { 6 r = q; 7 q = p; 8 p = p->next; 9 q->next = r; 10 } 11 12 return q; 13 } 14 15 ListNode *bmiddleNode(ListNode *head) { 16 ListNode *fast, *slow; 17 fast = slow = head; 18 while (fast->next && fast->next->next) { 19 fast = fast->next->next; 20 slow = slow->next; 21 } 22 23 return slow; 24 } 25 26 public: 27 void reorderList(ListNode *head) { 28 ListNode *bmid = bmiddleNode(head); 29 ListNode *rev = reverseList(bmid->next); 30 bmid->next = nullptr; 31 32 ListNode top, *tmp = &top, *a, *b, *an; 33 for (a = head, b = rev; b; b = b->next, a = an) { 34 an = a->next; 35 tmp = tmp->next = a; 36 tmp = tmp->next = b; 37 } 38 if (a) tmp = tmp->next = a; 39 tmp->next = nullptr; 40 } 41 };