Greatest Common Divisor (GCD) — Euclidean?

Short answer: Algorithm int GCD(int a, int b) { Follow on: while (b != 0) {

Example code

int temp = b;
b = a % b;
a = temp;
}
return a;
} Explanation: Repeatedly replace (a, b) with (b, a mod b) until b is 0; then a is the GCD.

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.