MatchSpecificPattern

class GfG{
    static String encode(String s)
    {
        HashMap<Character, Integer> hm = new HashMap<Character, Integer>();
        int i = 0;
        String res = "";
        for(int j=0 ; j<s.length() ; j++)
        {
            if(!hm.containsKey(s.charAt(j)))
                hm.put(s.charAt(j), i++);
            res += hm.get(s.charAt(j));
        }
        return res;
    }
    public static ArrayList<String> findMatchedWords(ArrayList<String> dict, String pattern)
	{
	    ArrayList<String> al = new ArrayList<String>();
	    String hash = encode(pattern);
	    for(int i=0 ; i<dict.size() ; i++)
	    {
	        String s = dict.get(i);
	        if(s.length() == pattern.length() && encode(s).equals(hash))
	            al.add(s);
	    }
	    return al;
	}
}