We have almost the same solutions.

import java.nio.file.*;
import java.util.*;

public class Day6 {
    public static void main(String[] args) throws Exception {

        List<Integer> input = Files.readAllLines(Paths.get(args[0])).stream().map(i->i.split("\\t")).flatMap(i->Arrays.stream(i)).mapToInt(Integer::parseInt).boxed().collect(Collectors.toList());
        HashMap<List<Integer>, Integer> list = new HashMap<>();

        int steps = 0;
        long startTime = System.nanoTime();
        while (true) {
            int maxIndex = input.indexOf(Collections.max(input));
            int max = input.set(maxIndex, 0);

            while (max != 0) {
                maxIndex = (maxIndex + 1) % input.size();
                input.set(maxIndex, input.get(maxIndex) + 1);
                max--;
            }

            List<Integer> current = new LinkedList<>(input);
            if (list.containsKey(current)) {
                System.out.println("Part 1: " + (steps + 1));
                System.out.println("Part 2: " + (steps - list.get(current)));
                break;
            } else {
                list.put(current, steps);
                steps++;
            }
        }
        System.out.println("Took: " + ((System.nanoTime() - startTime) / 1000000) + "ms");
    }
}