92. Reverse Linked List II
Reverse a linked list from position m to n. Do it in one-pass.
Note: 1 ≤ m ≤ n ≤ length of list.
Example:
Input: 1->2->3->4->5->NULL, m = 2, n = 4
Output: 1->4->3->2->5->NULL
func reverseBetween(head *ListNode, m int, n int) *ListNode {
dummy := ListNode{Val: 0}
dummy.Next = head
node := &dummy
for i := 1; i < m; i++ {
node = node.Next
}
pre := node
curr := node.Next
tail := curr
for i := m; i <= n; i++ {
nxt := curr.Next
curr.Next = pre
pre = curr
curr = nxt
}
tail.Next = curr
node.Next = pre
return dummy.Next
}
