My solution to HackerRank Challenge “Strings: Making Anagrams”

This is my solution to challenge “Strings: Making Anagrams” on HackerRank. Click here to see the challenge.

import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;
public class Solution {
    
    
    public static int numberNeeded(String first, String second) {
        int[] charCountsForFirstString = getCharCounts(first);
        int[] charCountsForSecondstring = getCharCounts(second);
        return getDifference(charCountsForFirstString,charCountsForSecondstring);

    }
    public static int getDifference(int[] array1, int[] array2){
         if(array1.length != array2.length){
             return -1;
         }
         int diff = 0;
         for (int i=0; i < array1.length; i++){
             diff += Math.abs(array1[i] - array2[i]);
         }
        return diff;
    }
    public static int[] getCharCounts(String word){
        int[] charCounts = new int[26];
        for (int i =0;i < word.length() ; i++){
            int offset = (int) 'a';
            int n = word.charAt(i) - offset; // it will represent A as 0, B as 2 and so on.
            charCounts[n]++; 
        }
        return charCounts;
    }
  
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String a = in.next();
        String b = in.next();
        System.out.println(numberNeeded(a, b));
    }
}