Leetcode 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") -> [code]false

isUnique("cart") ->

true

isUnique("cane") ->

false

isUnique("make") ->

true

解题关键点有3个：[/code]
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<String, String> map = new HashMap<String, String>();
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");