160. Intersection of Two Linked Lists

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None
class Solution:
    def getIntersectionNode(self, headA: ListNode, headB: ListNode) -> ListNode:
        pointer_a = headA
        pointer_b = headB

        # basically, append list a onto list b and
        # vice-versa and traverse both simultaneously
        while pointer_a != pointer_b:
            if not pointer_a:
                pointer_a = headB
            else:
                pointer_a = pointer_a.next
            
            if not pointer_b:
                pointer_b = headA
            else:
                pointer_b = pointer_b.next

        return pointer_a