Lexicographically comparing two strings

Question

I am trying to find out lexicographically smallest and largest substring of length z which is taken from input. I don't know why but the if condition is not working where I am trying to find the minimum substring.

import java.io.*;
import java.util.*;

public class Solution {

    public static void main(String[] args) {

        Scanner ip=new Scanner(System.in);

        String s=ip.next();
        int z=ip.nextInt();
        String max="";
        String mini="";
        String x="";

        for(int i=0;i<s.length()-z;i++) {
                x=s.substring(i,i+z);
                if(x.compareTo((mini))<0) //this is not working
                    mini=x;

                if(x.compareTo((max))>0)
                    max=x;
            }
        System.out.print(mini);
        System.out.print(max);
    }
}

see the code where i am trying to find minimum substring,it is not working — Eduardo, Jun 10 '17 at 08:21
you have initially declared mini as empty string so it is not changing. You should initialize both mini and max as any z-length substring of the input string. `mini = max = s.substring(0, z);` — Rahul Jain, Jun 10 '17 at 08:36

Oghli · Accepted Answer · 2017-06-10T09:22:55.797

The problem in declaring of both variables mini and max

you already initialize them as empty string so the condition will not return the expected result when comparing them to x and their values won't change

you can initialize them:

 mini = s.substring(0, z);
 max  = s.substring(0, z);

Edit:

if you try to test this condition :

x.compareTo(("")) it will always return value bigger than 0 so mini won't change at any case.

Lexicographically comparing two strings

1 Answers1