题解 | #链表内指定区间反转#
链表内指定区间反转
http://www.nowcoder.com/practice/b58434e200a648c589ca2063f1faf58c
[链表内指定区间反转]
我感觉我好蠢啊...
不过还是做出来了
Java代码如下：
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) {
ListNode flag = head;
ListNode beforeReverse = null;
int index = 1;
while (index != m) {
beforeReverse = flag;
flag = flag.next;
index++;
}
ListNode node = flag;
if (n == m) {
return head;
} else if (n - m == 1) {
flag = flag.next;
node.next = flag.next;
flag.next = node;
if (beforeReverse != null) {
beforeReverse.next = flag;
return head;
} else {
return flag;
}
}
ListNode before = flag;
flag = flag.next;
ListNode after = flag.next;
while (index != n) {
flag.next = before;
before = flag;
flag = after;
if (after != null) {
after = after.next;
}
index++;
}
if (beforeReverse != null) {
beforeReverse.next.next = flag;
beforeReverse.next = before;
return head;
} else {
node.next = flag;
return before;
}
}
}
投递字节跳动等公司10个岗位 >
