algorithm/Week_01/id_101/LeetCode_25_101.java at master · feixiangcode/algorithm · GitHub

History

58 lines (55 loc) · 1.53 KB

Raw

package linkedlist.reverseNodesInkGroup;

import linkedlist.ListNode;

/**

* @author Seina

* @version 2019-01-20 18:50:06

public class ReverseNodesInkGroup {

/**

* @param head 链表第一个结点

* @param k:是一个正整数，他的值小于或等于链表的长度

* @return 反转后的链表第一个结点

public ListNode reverseKGroup(ListNode head, int k) {

//k等于1，每1个结点进行翻转，相当于直接返回原始链表

if (k < 2) {

return head;

}

ListNode start;

ListNode pre = null;

ListNode cur = head;

ListNode next;

int count = 1;

while (cur != null) {

next = cur.next;

if (count == k) {

start = pre == null ? head : pre.next;

//head用来追踪链表反转过程中的第一个结点

head = pre == null ? cur : head;

resign(pre, start, cur, next);

pre = start;

count = 0;

}

count++;

cur = next;

}

return head;

}

private void resign(ListNode left, ListNode start, ListNode end,

ListNode right) {

ListNode p = start;

ListNode c = start.next;

ListNode n;

while (c != right) {

n = c.next;

c.next = p;

p = c;

c = n;

}

if (left != null) {

left.next = end;

}

start.next = right;

}

algorithm/Week_01/id_101/LeetCode_25_101.java at master · feixiangcode/algorithm · GitHub

Expand file tree

Breadcrumbs

LeetCode_25_101.java

Latest commit

History

Breadcrumbs

LeetCode_25_101.java

File metadata and controls