Partition List

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution:
    def partition(self, head: ListNode, x: int) -> ListNode:
        if(head is None):
            return None
        elif(head.next==None):
            return head
        else:
            first=head
            y=None
            xx=None
            curx=None
            sx=None
            last=None
            while(first is not None):
                if(first.val<x):
                    if(xx is None):
                        xx=ListNode(first.val)
                        xx.next=None
                        curx=xx
                    else:
                        sx=ListNode(first.val)
                        curx.next=sx
                        curx=sx
                        sx=None
                else:
                    if(y is None):
                        y=ListNode(first.val)
                        y.next=None
                        cury=y
                    else:
                        sy=ListNode(first.val)
                        cury.next=sy
                        cury=sy
                        sy=None
                first=first.next
            if(curx!=None):
                curx.next=y
                return xx  
            else:
                return y