86. 分隔链表

class Solution {
    public ListNode partition(ListNode head, int x) {
        /**
        开两个节点  big  small  
        bigHead smallHead放他们的头(而且是亚节点)
        遍历head
            <x  small.next指向他
            >x  big.next指向他
         */
         ListNode big=new ListNode(0);
        ListNode bigHead=big;
         ListNode small =new ListNode(0);
         ListNode smallHead=small;

        //我们操作bigHead smallHead就可
         while(head!=null){
             if(head.val>=x){
                bigHead.next=head;
                bigHead=bigHead.next;
             }else if(head.val<x){
                smallHead.next=head;
                smallHead=smallHead.next;
             }
             head=head.next;
         }
         bigHead.next=null;
         smallHead.next=big.next;
         return small.next;
    }
}