KotlinKronicles02.kt

// THE KOTLIN WAY

// 1. Who did maximum number of transactions
val maxTransactionsBy = customers.maxBy { it.transactions.count() }

// List all transactions irrespective of customers
val transactions = customers.flatMap { it.transactions }

// 2a. Get total amount deposited in the bank (use transactions constant from above)
val totalAmountDeposited = transactions.filter { it.type == "deposit" }.sumByDouble { it.amount }

// 2b. Get total amount withdrawn from the bank (use transactions constant from above)
val totalAmountWithdrawn = transactions.filter { it.type == "withdraw" }.sumByDouble { it.amount }

// 3. What is the net amount deposited?
val netAmountDeposited = transactions.fold(0.0) { amount, transaction ->
    when (transaction.type) {
        "deposit" -> amount + transaction.amount
        "withdraw" -> amount - transaction.amount
        else -> amount
    }
}

// 4. The Bank require customers to keep a minimum balance of 1500.00
// Create lists of customers with balance BELOW and ABOVE minimum allowed balance
val minimumAllowedLimit = 1500.0
val (lowBalanceCustomers, highBalanceCustomers) = customers.partition { it.balance < minimumAllowedLimit }