Find the intersection node of two linked lists (if any)?

Short answer: ListNode GetIntersectionNode(ListNode headA, ListNode headB) {

Example code

if (headA == null || headB == null) return null;
ListNode a = headA, b = headB; while (a != b) { a = (a == null) ? headB : a.next;
b = (b == null) ? headA : b.next;
}
return a; // either intersection or null
} Explanation: Two pointers traverse both lists; if no intersection, both will reach null simultaneously.

Real-world example (ShopNest)

In coding rounds, state complexity aloud, write a clear ShopNest-flavored example (orders, carts), then handle edge cases (empty list, null, overflow).

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.