/**
* Definition for singly-linked list.
* function ListNode(val) {
* this.val = val;
* this.next = null;
* }
*/
/**
* @param {ListNode} headA
* @param {ListNode} headB
* @return {ListNode}
*/
var getIntersectionNode = function (headA, headB) {
let a1 = headA;
let b1 = headB;
while (a1 !== b1) {
if (a1 === null) {
a1 = headB;// 链表 A 走完了,将 a1 指向 headB 继续遍历
} else {
a1 = a1.next;// 链表 A 一直往下走
}
if (b1 === null) {
b1 = headA;// 链表 B 走完了,将 b1 指向 headA 继续遍历
} else {
b1 = b1.next;// 链表 B 一直往下走
}
}
return a1;
};