LeetCode#203 Count Prime

Problem Definition:

Remove all elements from a linked list of integers that have value val.

Example
Given: 1 --> 2 --> 6 --> 3 --> 4 --> 5 --> 6, val = 6
Return: 1 --> 2 --> 3 --> 4 --> 5

Solution: 构造一个头节点

def removeElements(self, head, val):
        fake=ListNode(0)
        fake.next=head
        pb=fake
        p=head
        while p!=None:
            if p.val==val:
                pb.next=p.next #delete
            else:
                pb=p           #skip
            p=p.next
        return fake.next