链表内指定区间反转

import java.util.*;

/*

* public class ListNode {

* int val;

* ListNode next = null;

* }

*/

public class Solution {

/**

*

* @param head ListNode类

* @param m int整型

* @param n int整型

* @return ListNode类

*/

public ListNode reverseBetween (ListNode head, int m, int n) {

if (head == null || n < m || n == 0) {

return head;

}

ListNode reverseNode = new ListNode(0);

reverseNode.next = head;

ListNode pre = reverseNode;

for (int i = 1; i < m; i++) {

pre = pre.next;

}

ListNode curr = pre.next;

while (n-- > m) {

ListNode temp = curr.next;

curr.next = temp.next;

temp.next = pre.next;

pre.next = temp;

}

return reverseNode.next;

}

}