示例 1：

输入：intersectVal = 8, listA = [4,1,8,4,5], listB = [5,0,1,8,4,5], skipA = 2, skipB = 3输出：Reference of the node with value = 8输入解释：相交节点的值为 8 （注意，如果两个列表相交则不能为 0）。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]。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。
来源：力扣（LeetCode）链接：https://leetcode-cn.com/problems/liang-ge-lian-biao-de-di-yi-ge-gong-gong-jie-dian-lcof著作权归领扣网络所有。商业转载请联系官方授权，非商业转载请注明出处。

/** * Definition for singly-linked list. * public class ListNode { *     int val; *     ListNode next; *     ListNode(int x) { *         val = x; *         next = null; *     } * } */public class Solution {    public ListNode getIntersectionNode(ListNode headA, ListNode headB) {        if (headA == null || headB == null) {            return null;        }        Set<ListNode> set = new HashSet<>();        while (headA != null) {            set.add(headA);            headA = headA.next;        }        while (headB != null) {            if (set.contains(headB)) {                return headB;            }            headB = headB.next;        }        return null;    }}

/** * Definition for singly-linked list. * public class ListNode { *     int val; *     ListNode next; *     ListNode(int x) { *         val = x; *         next = null; *     } * } */public class Solution {    public ListNode getIntersectionNode(ListNode headA, ListNode headB) {        if (headA == null || headB == null) {            return null;        }        ListNode p1 = headA, p2 = headB;        while (p1 != p2) {            p1 = (p1 == null) ? headB : p1.next;            p2 = (p2 == null) ? headA : p2.next;        }
        return p1;    }}