Editorial

If the maximum prime divisor of $x$ is greater than $d$, then the answer is $-1$. This is because to obtain a product equal to $n$, all its prime divisors must be used.

To find an array of minimum length, you can follow the same greedy algorithm:

• if the number is equal to $1$, then finish the work.

• let $k$ be the maximum divisor of $x$ that is not greater than $d$. Write the number $k$ to the array and divide $x$ by $k$.

Finding the divisor can be done with a complexity of $O(\sqrt{x})$.