Insecure Randomness — Use a Cryptographic Source

A password-reset token generator is meant to build a token from a caller-supplied source of cryptographically-random integers.

The bug: the buggy version ignores the secure source entirely and calls Math.random() instead — Math.random is a fast, statistically-predictable PRNG never intended for security purposes; tokens generated from it can be predicted or brute-forced far more easily than a real attacker should need.

Your task: fix solve(randomInts) so it builds the token from the provided `randomInts` array (mapping each integer to a character via % alphabet.length), never by generating its own randomness internally.