问如何使用长度为k的java中按字典顺序排列的最小和最大子字符串？

EN

public static void main(String[] args) {
    // TODO Auto-generated method stub

    Scanner sc = new Scanner(System.in);
    String inputString = sc.nextLine();
    int length = sc.nextInt();
    String smallest="";
    String largest="";
    for(int i = 0;i<=inputString.length()-length+1;i++){
        String subString = inputString.substring(i,i+length);
        if(i == 0){
            smallest = subString;
        }
        if(subString.compareTo(largest)>0){
            largest = subString;
        }else if(subString.compareTo(smallest)<0)
            smallest = subString;
    }
    System.out.println(smallest);
    System.out.println(largest);
}

public static void main(String[] args) {
    // TODO Auto-generated method stub

    Scanner sc = new Scanner(System.in);
    String inputString = sc.nextLine();
    int length = sc.nextInt();
    String smallest="";
    String largest="";
    for(int i = 0;i<=inputString.length()-length;i++){
        String subString = inputString.substring(i,i+length);
        if(i == 0){
            smallest = subString;
        }
        if(subString.compareTo(largest)>0){
            largest = subString;
        }else if(subString.compareTo(smallest)<0)
            smallest = subString;
    }
    System.out.println(smallest);
    System.out.println(largest);
}