LeetCode-Unique Word Abbreviation

LiBlog發表於2016-08-30

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

Solution:
 1 public class ValidWordAbbr {
 2     Map<String, String> abbrMap;
 3 
 4     public ValidWordAbbr(String[] dictionary) {
 5         abbrMap = new HashMap<String, String>();
 6 
 7         for (String word : dictionary) {
 8             String abbr = getAbbr(word);
 9             // the abbr is invalid, if it exsits and the corresponding word is not current word.
10             if (abbrMap.containsKey(abbr) && !abbrMap.get(abbr).equals(word)) {
11                 abbrMap.put(abbr, "");
12             } else {
13                 abbrMap.put(abbr, word);
14             }
15         }
16     }
17 
18     public boolean isUnique(String word) {
19         String abbr = getAbbr(word);
20         // true, if @abbr does not exsit or the corresponding word is the @word.
21         return (!abbrMap.containsKey(abbr)) || (abbrMap.containsKey(abbr) && abbrMap.get(abbr).equals(word));
22     }
23 
24     public String getAbbr(String word){
25     if (word.length()<=2) return word;
26 
27     StringBuilder builder = new StringBuilder();
28     builder.append(word.charAt(0));
29     builder.append(word.length()-2);
30     builder.append(word.charAt(word.length()-1));
31 
32     return builder.toString();
33     }
34 }
35 
36 // Your ValidWordAbbr object will be instantiated and called as such:
37 // ValidWordAbbr vwa = new ValidWordAbbr(dictionary);
38 // vwa.isUnique("Word");
39 // vwa.isUnique("anotherWord");

 

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