day 39

题目描述

思路

遍历链表，每一个点与值比较，比值小就继续，比值大就放到链表尾部即可

/*** Definition for singly-linked list.* public class ListNode {*     int val;*     ListNode next;*     ListNode() {}*     ListNode(int val) { this.val = val; }*     ListNode(int val, ListNode next) { this.val = val; this.next = next; }* }*/
class Solution {public ListNode partition(ListNode head, int x) {if(head==null){return null;}ListNode fakehead=new ListNode();fakehead.next=head;ListNode z=head;while(z.next!=null){z=z.next;}ListNode before=fakehead;ListNode y=head;ListNode end=z;while(y!=end){if(y.val>=x){z.next=y;before.next=y.next;y=y.next;z=z.next;z.next=null;}else{before=before.next;y=y.next;}}if(y.val>=x){z.next=y;before.next=y.next;y=y.next;z=z.next;z.next=null;}return fakehead.next;}
}