// Write a program to find the node at which the intersection of two singly linked lists begins.


// For example, the following two linked lists:

// A:          a1 → a2
//                    ↘
//                      c1 → c2 → c3
//                    ↗
// B:     b1 → b2 → b3
// begin to intersect at node c1.


// Notes:

// If the two linked lists have no intersection at all, return null.
// The linked lists must retain their original structure after the function returns.
// You may assume there are no cycles anywhere in the entire linked structure.
// Your code should preferably run in O(n) time and use only O(1) memory.

// Write a program to find the node at which the intersection of two singly linked lists begins.


// For example, the following two linked lists:

// A:          a1 → a2
//                    ↘
//                      c1 → c2 → c3
//                    ↗
// B:     b1 → b2 → b3
// begin to intersect at node c1.


// Notes:

// If the two linked lists have no intersection at all, return null.
// The linked lists must retain their original structure after the function returns.
// You may assume there are no cycles anywhere in the entire linked structure.
// Your code should preferably run in O(n) time and use only O(1) memory.

/**
 * Definition for singly-linked list.
 * function ListNode(val) {
 *     this.val = val;
 *     this.next = null;
 * }
 */

/**
 * @param {ListNode} headA
 * @param {ListNode} headB
 * @return {ListNode}
 */

add params