HackerRank - Cracking Code Interview - Strings: Making Anagrams (https://www.hackerrank.com/challenges/ctci-making-anagrams)

Solution.java

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) {
      Map<Character, Integer> fmap = getCharacterMap(first);
        
      int count = 0;
        
      for (char c : second.toCharArray()) {
          if (!fmap.containsKey(c)) count++;
          else if (fmap.containsKey(c) && fmap.get(c) == 0) count++;
          else if (fmap.containsKey(c) && fmap.get(c) > 0) {
              Integer current = fmap.get(c);
              current--;
              fmap.put(c, current);
          }
      }
        
      for (Integer value : fmap.values()) {
          count = count + value;
      }
        
      return count;
    }
    
    private static Map<Character, Integer> getCharacterMap(String value) {
      Map<Character, Integer> fmap = new HashMap<Character, Integer>();
        
      for (char c : value.toCharArray()) {
          if (!fmap.containsKey(c)) fmap.put(c, 1);
          else {
              Integer current = fmap.get(c);
              current++;
              fmap.put(c, current);
          }
      }
        
       return fmap;
    }
  
    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));
    }
}