/**
 * Given a list of transactions, find the unique account numbers.
 *
 * @param transactions List of transactions, each transaction contains the account number.
 * @return Set of unique account numbers.
 */
fun findUniqueAccounts(transactions: List<Map<String, String>>): Set<String> {

    val uniqueAccounts = mutableSetOf<String>()  // Create an empty set to store the unique account numbers

    for (transaction in transactions) {
        val accountNumber = transaction["account_number"]

        // Add the account number to the uniqueAccounts set if it doesn't already exist
        accountNumber?.let { uniqueAccounts.add(it) }
    }

    return uniqueAccounts
}
/**
 * Given a list of transactions, find the unique account numbers.
 *
 * @param transactions List of transactions, each transaction contains the account number.
 * @return Set of unique account numbers.
 */
fun findUniqueAccounts(transactions: List<Map<String, String>>): Set<String> {
/**
 * Given a list of transactions, find the unique account numbers.
 *
 * @param transactions List of transactions, each transaction contains the account number.
 * @return Set of unique account numbers.
 */
fun findUniqueAccounts(transactions: List<Map<String, String>>): Set<String> {

    val uniqueAccounts = mutableSetOf<String>()  // Create an empty set to store the unique account numbers

    for (transaction in transactions) {
        val accountNumber = transaction["account_number"]

        // Add the account number to the uniqueAccounts set if it doesn't already exist
        accountNumber?.let { uniqueAccounts.add(it) }
    }

    return uniqueAccounts
}