{ "data": { "question": { "questionId": "1000259", "questionFrontendId": "剑指 Offer II 023", "categoryTitle": "LCOF2", "boundTopicId": 910262, "title": "两个链表的第一个重合节点", "titleSlug": "3u1WK4", "content": "

English description is not available for the problem. Please switch to Chinese.

\n", "translatedTitle": "两个链表的第一个重合节点", "translatedContent": "

给定两个单链表的头节点 headA 和 headB ，请找出并返回两个单链表相交的起始节点。如果两个链表没有交点，返回 null 。

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图示两个链表在节点 c1 开始相交：

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题目数据保证整个链式结构中不存在环。

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注意，函数返回结果后，链表必须 保持其原始结构 。

\n\n

\n\n

示例 1：

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\n\n

\n输入：intersectVal = 8, listA = [4,1,8,4,5], listB = [5,0,1,8,4,5], skipA = 2, skipB = 3\n输出：Intersected at '8'\n解释：相交节点的值为 8 （注意，如果两个链表相交则不能为 0）。\n从各自的表头开始算起，链表 A 为 [4,1,8,4,5]，链表 B 为 [5,0,1,8,4,5]。\n在 A 中，相交节点前有 2 个节点；在 B 中，相交节点前有 3 个节点。\n

\n\n

示例 2：

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\n\n

\n输入：intersectVal = 2, listA = [0,9,1,2,4], listB = [3,2,4], skipA = 3, skipB = 1\n输出：Intersected at '2'\n解释：相交节点的值为 2 （注意，如果两个链表相交则不能为 0）。\n从各自的表头开始算起，链表 A 为 [0,9,1,2,4]，链表 B 为 [3,2,4]。\n在 A 中，相交节点前有 3 个节点；在 B 中，相交节点前有 1 个节点。\n

\n\n

示例 3：

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\n\n

\n输入：intersectVal = 0, listA = [2,6,4], listB = [1,5], skipA = 3, skipB = 2\n输出：null\n解释：从各自的表头开始算起，链表 A 为 [2,6,4]，链表 B 为 [1,5]。\n由于这两个链表不相交，所以 intersectVal 必须为 0，而 skipA 和 skipB 可以是任意值。\n这两个链表不相交，因此返回 null 。\n

\n\n

\n\n

提示：

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listA 中节点数目为 m
listB 中节点数目为 n
0 <= m, n <= 3 * 10⁴
1 <= Node.val <= 10⁵
0 <= skipA <= m
0 <= skipB <= n
如果 listA 和 listB 没有交点，intersectVal 为 0
如果 listA 和 listB 有交点，intersectVal == listA[skipA + 1] == listB[skipB + 1]

\n\n

\n\n

进阶：能否设计一个时间复杂度 O(n) 、仅用 O(1) 内存的解决方案？

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\n\n

注意：本题与主站 160 题相同：https://leetcode-cn.com/problems/intersection-of-two-linked-lists/

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