public class Test {
    public static void main(String[] args) throws Throwable {
        final int numWheels = 4;
        final int numSymbols = 8;
        final long threeOfAKindPayout = 17;
        final long fourOfAKindPayout = 200;
//        final long threeOfAKindPayout = 200;
//        final long fourOfAKindPayout = 20_000;

        int totalCombinations = numSymbols;
        for (int i = 0; i < numWheels - 1; ++i) {
            totalCombinations *= numSymbols;
        }

        System.out.println("Number of symbols: " + numSymbols);
        System.out.println("Number of wheels: " + numWheels);

        List<Consumer<Deque<Integer>>> conditionCheckers = new ArrayList<>();

        AtomicInteger numThreeOfAKind = new AtomicInteger(0);
        Consumer<Deque<Integer>> threeOfAKindChecker = (values) -> {
            boolean isThreeOfAKind = values.stream()
                    .collect(Collectors.groupingBy(k -> k, counting())).entrySet().stream()
                    .anyMatch(e -> e.getValue() == 3);
            if (isThreeOfAKind) {
                numThreeOfAKind.incrementAndGet();
                System.out.print("<3oaK> ");
            }
        };
        conditionCheckers.add(threeOfAKindChecker);

        printValues(numWheels, numSymbols, new LinkedList<>(), conditionCheckers);

        long totalPayouts = numThreeOfAKind.get() * threeOfAKindPayout + numSymbols * fourOfAKindPayout;
        float averagePayout = totalPayouts / (float) totalCombinations;

        System.out.println("Total combinations: " + totalCombinations);
        System.out.println("Total three-of-a-kind: " + numThreeOfAKind.get());
        System.out.println("Total four-of-a-kind: " + numSymbols);
        System.out.println("Average payout: " + averagePayout);
    }

    private static void printValues(int wheelsRemaining, int numSymbols, Deque<Integer> values,
            List<Consumer<Deque<Integer>>> conditionCheckers) {
        if (wheelsRemaining == 0) {
            values.stream().forEach(v -> System.out.print(v + " "));
            conditionCheckers.stream().forEach(c -> c.accept(values));
            System.out.println("");
            return;
        }

        for (int i = 0; i < numSymbols; ++i) {
            values.push(i + 1);
            printValues(wheelsRemaining - 1, numSymbols, values, conditionCheckers);
            values.pop();
        }
    }
}