Unique Word Abbreviation

An abbreviation of a word follows the form <first letter><number><last letter>. Below are some examples of word abbreviations:

a) it                      --> it    (no abbreviation)

     1
b) d|o|g                   --> d1g

              1    1  1
     1---5----0----5--8
c) i|nternationalizatio|n  --> i18n

              1
     1---5----0
d) l|ocalizatio|n          --> l10n

Assume you have a dictionary and given a word, find whether its abbreviation is unique in the dictionary. A word's abbreviation is unique if no other word from the dictionary has the same abbreviation.

Example:

Given dictionary = [ "deer", "door", "cake", "card" ]

isUnique("dear") -> false
isUnique("cart") -> true
isUnique("cane") -> false
isUnique("make") -> true

解题关键点有3个：

1. 找出word abbreviation 的规律，<first letter><number><last letter>，number = string.length() - 2

2. 当发现dictionary 里有相同的abbreviation, key 对应的value 变为""

3. The abbreviation of "hello", i.e., h3o already exists in the dictionary.

Input: ["hello"],isUnique("hello") Output: [false] Expected: [true]

If the given word itself is in the dictionary, and it has the unique abbreviation, then we should return true.

 public class ValidWordAbbr {
     private Map<String, String> map = new HashMap<String, String>();

     public ValidWordAbbr(String[] dictionary) {
         for(int i = ; i < dictionary.length; i++){
             String key = abbreviate(dictionary[i]);
             if(!map.containsKey(key)){
                 map.put(key, dictionary[i]);
             }else{
                 map.put(key, "");
             }
         }
     }

     private String abbreviate(String str){
         return str.charAt() + Integer.toString(str.length() - )+ str.charAt(str.length()-);
     }

     public boolean isUnique(String word) {
         String x = abbreviate(word);
         if(map.containsKey(x)){
             if(map.get(x).equals(word)){
                 return true;
             }else {
                 return false;
             }
         }
         return true;
     }
 }

 // Your ValidWordAbbr object will be instantiated and called as such:
 // ValidWordAbbr vwa = new ValidWordAbbr(dictionary);
 // vwa.isUnique("Word");
 // vwa.isUnique("anotherWord");