I was referred to Google by an HR contact I know. I had interviewed on March 4th, 2020. The interviewer was polite and nice.

The question I was asked was: Given a set of prime numbers, return all possible composite numbers from the given set (including the given numbers). For example: Input: [2, 3, 5] Output: [1, 2, 3, 5, 6, 10, 15, 30]

I gave a solution that had a time complexity of 2^n. My approach was to initialize a set like this: {1}. Then, take each element of the array and multiply it with the elements in the result set. Start: {1}

i = 0: {1, 2}

i = 1: {1, 2, 3, 6}

And so on.

Two days later, I was informed that I was not selected.

The question I was asked was: Given a set of prime numbers, return all possible composite numbers that can be formed from the given set (including the given numbers themselves).