LargestNumber

MaxNumber.java

/*
Given a list of non negative integers, arrange them such that they form the largest number.

For example, given [3, 30, 34, 5, 9], the largest formed number is 9534330.

Note: The result may be very large, so you need to return a string instead of an integer.
*/
public class MaxNumber {

    String getLargestNumber(List<Integer> numbers) {

        if (numbers == null || numbers.isEmpty()) return "";

        List<String> strings = numbers.stream().map(e -> e.toString())
                .sorted((o11, o21) -> (o21 + o11).compareTo(o11 + o21))
                .collect(Collectors.toList());

        return String.join("", strings);
    }

    public static void main(String[] args) {
        MaxNumber maxNumber = new MaxNumber();

        List<Integer> integers = Arrays.asList(1, 32, 98, 9, 12);
        System.out.println(maxNumber.getLargestNumber(integers));

        integers = Arrays.asList(50, 2, 1, 9);
        System.out.println(maxNumber.getLargestNumber(integers));

    }
}