AdventOfCode2017/Day6

Day6Part1.java

 public static void main(String[] args) throws IOException {
 
        List<Integer> nums = Arrays.stream(Files.readAllLines(Paths.get(new File("res/day6").getPath())).get(0)
                            .split("\\s+"))
                .mapToInt(Integer::parseInt)
                .boxed()
                .collect(Collectors.toList());
 
        Map<List<Integer>, Integer> seen = new HashMap<>();
 
        seen.put(nums, 0);
        int steps = 0;
 
        while (true) {
            int index = firstMax(nums);
            int redistribute = nums.get(index);
            nums.set(index++, 0);
            while (redistribute-- > 0) {
                index %= nums.size();
                nums.set(index, nums.get(index++) + 1);
            }
            steps++;
 
            if (seen.containsKey(nums)) {
               
                break;
            }
            seen.put(nums, steps);
 
 
        }
        
    }
    private static int firstMax(List<Integer> a) {
        int max = Collections.max(a);
        for (int i = 0; i < a.size(); i++) {
            if (a.get(i).equals(max)) return i;
        }
        return 0;
    }

Day6Part2.java

 public static void main(String[] args) throws IOException {
 
        List<Integer> nums = Arrays.stream(Files.readAllLines(Paths.get(new File("res/day6").getPath())).get(0)
                            .split("\\s+"))
                .mapToInt(Integer::parseInt)
                .boxed()
                .collect(Collectors.toList());
 
        Map<List<Integer>, Integer> seen = new HashMap<>();
 
        seen.put(nums, 0);
        int steps = 0;
 
        while (true) {
            int index = firstMax(nums);
            int redistribute = nums.get(index);
            nums.set(index++, 0);
            while (redistribute-- > 0) {
                index %= nums.size();
                nums.set(index, nums.get(index++) + 1);
            }
            steps++;
 
            if (seen.containsKey(nums)) {
               System.out.println("Steps: " + (steps - seen.get(nums)));
                break;
            }
            seen.put(nums, steps);
 
 
        }
        
    }
    private static int firstMax(List<Integer> a) {
        int max = Collections.max(a);
        for (int i = 0; i < a.size(); i++) {
            if (a.get(i).equals(max)) return i;
        }
        return 0;
    }