题解 | #链表内指定区间反转#

package main
import . "nc_tools"

//头插法
func reverseBetween( head *ListNode ,  m int ,  n int ) *ListNode {
    // write code here
    if head == nil || head.Next == nil {
        return head 
    }

    dummy := &ListNode{Next : head}
    pre := dummy

    for i := 1; i < m; i++ {
        pre = pre.Next
    }

    cur := pre.Next
    for i := m; i < n; i++ {
        temp := cur.Next
        cur.Next = temp.Next
        temp.Next = pre.Next
        pre.Next = temp
    }
    return dummy.Next
}