牛客网 | 链表分割

题目描述

编写代码，以给定值x为基准将链表分割成两部分，所有小于x的结点排在大于或等于x的结点之前

给定一个链表的头指针 ListNode* pHead，请返回重新排列后的链表的头指针。注意：分割以后保持原来的数据顺序不变。

import java.util.*;/*public class ListNode {    int val;    ListNode next = null;    ListNode(int val) {        this.val = val;    }}*/public class Partition {    public ListNode partition(ListNode pHead, int x) {        // write code here        if(pHead==null||pHead.next==null) return pHead;        ListNode smallList = new ListNode(-1);        ListNode bigList = new ListNode(-1);        ListNode s = smallList;        ListNode b = bigList;        ListNode head = pHead;        while (head!=null)        {            if(head.val<x)            {                s.next = head;                s = s.next;            }            else            {                b.next = head;                b = b.next;            }            head = head.next;        }        b.next = null;        s.next = bigList.next;        return smallList.next;     }}