原题
给定一个链表和一个特定值 x,对链表进行分隔,使得所有小于 x 的节点都在大于或等于 x 的节点之前。
你应当保留两个分区中每个节点的初始相对位置。
示例:
输入: head = 1->4->3->2->5->2, x = 3 输出: 1->2->2->4->3->5
//分割链表(链表不带头结点) //算法实现时可以使用头结点,最后返回结果时去掉 class Solution { public ListNode partition(ListNode head, int x) { ListNode before_head = new ListNode(0); ListNode before = before_head; ListNode after_head = new ListNode(0); ListNode after = after_head; while (head != null) { if (head.val < x) { before.next = head; before = before.next; } else { after.next = head; after = after.next; } head = head.next; } after.next = null; before.next = after_head.next; return before_head.next; } }
参考链接:https://leetcode-cn.com/problems/partition-list/solution/fen-ge-lian-biao-by-leetcode/