Anagram.java

anagram

import java.lang.Character;
import java.util.Set;
import java.util.HashSet;

public class Anagram {
    public static void main(String [] args) {
        System.out.println(nAnagrams("AdnBndAndBdaBn", "dAn"));
        System.out.println(nAnagrams("AbrAcadAbRa", "cAda"));
    }

    static int nAnagrams(String parent, String child) {
        Set children = buildCharacterSet(child);
        int total = 0;

        for (int i = 0; i < parent.length() - (child.length() + 1); i++) {
            Set parentSubset = buildCharacterSet(parent.substring(i, i + child.length()));
            if (parentSubset.containsAll(children) && children.containsAll(parentSubset)) {
                total++;
            }
        }
        return total;
    }

    static Set buildCharacterSet(String s) {
        Set<Character> characterSet = new HashSet<>();
        for (int i = 0; i < s.length(); i++) {
            characterSet.add(s.charAt(i));
        }
        return characterSet;
    }
}