Ease the StockBroker

challenge.swift

func balanceStatements(_ list: String) -> String {
	var totalBuy = 0
	var totalSell = 0
	var malformedCount = 0
	var malformedOrders = [String]()

	let pattern = "\\w+ \\w+ \\d+\\.\\d+ \\w+"

	let orders = list.components(separatedBy: ",").filter { !$0.isEmpty }
	for order in orders {
		if let _ = order.range(of: pattern, options: .regularExpression) {
			let orderComponents = order.components(separatedBy: " ")
			let shares = Double(orderComponents[1]) ?? 0
			let amount = Double(orderComponents[2]) ?? 0
			if order.hasSuffix("B") {
				totalBuy += Int((shares * amount).rounded())
			} else {
				totalSell += Int((shares * amount).rounded())
			}
		} else {
			malformedOrders.append(order)
			malformedCount += 1
		}
	}

	let total = "Buy: \(totalBuy) Sell: \(totalSell)"
	return malformedOrders.count == 0 ? total : "\(total); Badly formed \(malformedCount): \(malformedOrders.joined(separator: " ;")) ;"
}