java_substring_comparison.java

/*
Input   ->  welcometojava
            3
Output  ->  ava
            wel
*/



import java.util.Scanner;

public class Solution {
    public static String getSmallestAndLargest(String s, int k) {
        String smallest = "";
        String largest = "";
        
        smallest = s.substring(0,k);
        largest  = "";
        for(int i=0;i<s.length()-k+1;i++){
        if(s.substring(i,i+k).compareTo(smallest) <0) smallest = s.substring(i,i+k);
        if(s.substring(i,i+k).compareTo(largest) >0) largest = s.substring(i,i+k); 
        }        
        return smallest + "\n" + largest;
    }

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        String s = scan.next();
        int k = scan.nextInt();      
        System.out.println(getSmallestAndLargest(s, k));
    }
}