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.
/** * Definition for singly-linked list. * public class ListNode { * int val; * ListNode next; * ListNode(int x) { * val = x; * next = null; * } * } */ public class Solution { public ListNode reverseBetween(ListNode head, int m, int n) { ListNode dummyHead=new ListNode(0); dummyHead.next=head; ListNode p=dummyHead; for(int i=1;i<m;i++){ p=p.next; } p.next=reverse(p.next,n-m+1); return dummyHead.next; } private ListNode reverse(ListNode head,int count){ ListNode pre=null; ListNode next=null; ListNode cur=head; for(int i=0;i<count;i++){ next=cur.next; cur.next=pre; pre=cur; cur=next; } head.next=next; return pre; } }
时间: 2024-10-19 07:40:35