21] Output: 3 Explanation: The GCD of 12, 15, and 21 is 3.

 Input: [24, 36, 48]
 Output: 12
 Explanation: The GCD of 24, 36, and 48 is 12.

Solution

The Greatest Common Divisor (GCD) of three or more numbers can be found by repeatedly computing the GCD of pairs of numbers.

To find the GCD of multiple numbers, we can iteratively compute the GCD of pairs of numbers:

For e.g. gcd between 3 numbers a,