/**
* Definition for singly-linked list.
* type ListNode struct {
* Val int
* Next *ListNode
* }
*/
func partition(head *ListNode, x int) *ListNode {
l1,l2:=new(ListNode),new(ListNode)
h1,h2:=l1,l2
for head!=nil{
if head.Val<x{
h1.Next=head
h1=h1.Next
}else{
h2.Next=head
h2=h2.Next
}
head=head.Next
}
h1.Next=l2.Next
h2.Next=nil
return l1.Next
}