Reverse Linked List II
Reverse a linked list from position m to n. Do it in-place and in one-pass.
For example:
Given 1->2->3->4->5->NULL, m = 2 and n = 4,
return 1->4->3->2->5->NULL.
Note:
Given m, n satisfy the following condition:
1 <= m <= n <= length of list.
Solution: in-place & one-pass.
1 class Solution {
2 public:
3 ListNode *reverseBetween(ListNode *head, int m, int n) {
4 ListNode dummy(0);
5 ListNode* pre = &dummy;
6 dummy.next = head;
7 for(int i = 0; i < m-1; i++) {
8 pre = pre->next;
9 }
10 ListNode* cur = pre->next;
11 for(int i = 0; i < n-m; i++) {
12 ListNode* move = cur->next;
13 cur->next = move->next;
14 move->next = pre->next;
15 pre->next = move;
16 }
17 return dummy.next;
18 }
19 };

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