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)     1b) d|o|g                   --> d1g              1    1  1     1---5----0----5--8c) i|nternationalizatio|n  --> i18n              1     1---5----0d) 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") -> falseisUnique("cart") -> trueisUnique("cane") -> falseisUnique("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.

1 public class ValidWordAbbr { 2     private Map
     
       map = new HashMap
      
       (); 3  4     public ValidWordAbbr(String[] dictionary) { 5         for(int i = 0; i < dictionary.length; i++){ 6             String key = abbreviate(dictionary[i]); 7             if(!map.containsKey(key)){ 8                 map.put(key, dictionary[i]); 9             }else{10                 map.put(key, "");11             }12         }13     }14     15     private String abbreviate(String str){16         return str.charAt(0) + Integer.toString(str.length() - 2)+ str.charAt(str.length()-1);17     }18 19     public boolean isUnique(String word) {20         String x = abbreviate(word);21         if(map.containsKey(x)){22             if(map.get(x).equals(word)){23                 return true;24             }else {25                 return false;26             }27         }28         return true;29     }30 }31 32 // Your ValidWordAbbr object will be instantiated and called as such:33 // ValidWordAbbr vwa = new ValidWordAbbr(dictionary);34 // vwa.isUnique("Word");35 // vwa.isUnique("anotherWord");