leetcode_reverse linked list ii

# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class :
    def reverseBetween(self, head: ListNode, m: int, n: int) -> ListNode:
        new_head = ListNode(0)
        new_head.next = head
        
        p_pre = new_head
        p_cur = head
        for i in range(1, m):
            p_pre = p_pre.next
            p_cur = p_cur.next
     
        for j in range(n-m):
            p_head = p_pre.next
            p_pre.next = p_cur.next
            p_temp =  p_cur.next
            p_cur.next = p_cur.next.next
            p_temp.next = p_head
           
        return new_head.next