python-leetcode-相交链表

160. 相交链表 - 力扣（LeetCode）

# 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) -> Optional[ListNode]:
        if not headA or not headB:
            return None

        pA, pB = headA, headB

        while pA != pB:
            # 当 pA 走完 A 链表后，跳到 B 链表
            pA = pA.next if pA else headB
            # 当 pB 走完 B 链表后，跳到 A 链表
            pB = pB.next if pB else headA

        return pA  # 若相交返回交点，否则返回 None