题解 | #链表内指定区间反转#
链表内指定区间反转
https://www.nowcoder.com/practice/b58434e200a648c589ca2063f1faf58c
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 (m == n) return head;
ListNode start = new ListNode(-1);
start.next = head;
ListNode p = start;
for (int i = 0; i < m - 1; i++) {
p = p.next;
}
ListNode ll = p, lr = p.next;
for (int i = 0; i < n - m + 1; i++) {
p = p.next;
}
ListNode rl = p, rr = p.next;
ll.next = null;
rl.next = null;
p = lr;
ListNode q = null, node = null;
while (p != null) {
q = p.next;
p.next = node;
node = p;
p = q;
}
ll.next = rl;
lr.next = rr;
return start.next;
}
}
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