UniqueWordAbbreviation.java

package easy;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

public class UniqueWordAbbreviation {

    private class ValidWordAbbr {
        private Map<String, String> dict;
        public ValidWordAbbr(String[] dictionary) {
            dict = new HashMap();
            for(String word : dictionary){
                String key = word.length() <= 2 ? word : (word.charAt(0) + String.valueOf(word.length()-2) + word.charAt(word.length()-1));
                if(dict.containsKey(key) && !dict.get(key).equals(word)){
                    dict.put(key, "");
                } else {
                    dict.put(key, word);
                }
            }
        }
        public boolean isUnique(String word) {
            String key = word.length() <= 2 ? word : (word.charAt(0) + String.valueOf(word.length()-2) + word.charAt(word.length()-1));
            if(!dict.containsKey(key)) return true;
            else return dict.get(key) != "" && dict.get(key).equals(word);
        }
    }
}

class ValidWordAbbr {

    private Map<String, Set<String>> dict;
    
    public ValidWordAbbr(String[] dictionary) {
        dict = new HashMap();
        for(String word : dictionary){
            String key = word.length() <= 2 ? word : (word.charAt(0) + String.valueOf(word.length()-2) + word.charAt(word.length()-1));
            if(dict.containsKey(key)){
                Set<String> set = dict.get(key);
                set.add(word);
                dict.put(key, set);
            } else {
                Set<String> set = new HashSet();
                set.add(word);
                dict.put(key, set);
            }
        }
    }

    public boolean isUnique(String word) {
        String key = word.length() <= 2 ? word : (word.charAt(0) + String.valueOf(word.length()-2) + word.charAt(word.length()-1));
        if(!dict.containsKey(key)) return true;
        else {
            Set<String> set = dict.get(key);
            if(set.size() != 1) return false;
            Iterator<String> it = set.iterator();
            return it.next().equals(word);
        }
    }
}