백준 18870번: 좌표 압축

public static void main(String[] args) throws IOException {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    br.readLine();
    Integer[] array = convertStringArrayToIntegerArray(br.readLine().split(" "));
    List<Integer> list = Arrays.asList(array.clone());

    Collections.sort(list);

    Map<Integer, Integer> map = new HashMap<>();
    int index = 0;
    for (int i : list) {
        if (!map.containsKey(i)) {
            map.put(i, index++);
        }
    }

    StringBuilder sb = new StringBuilder();
    for (int i : array) {
            sb.append(map.get(i)).append(" ");
    }

    System.out.println(sb.toString());
}

private static Integer[] convertStringArrayToIntegerArray(String[] args) {
    Integer[] array = new Integer[args.length];
    int i = 0;
    for (String str : args) {
        array[i++] = Integer.parseInt(str);
    }

    return array;
}