LeetCode 题解(256) : Unique Word Abbreviation

题目：

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

题解：

HashMap。

C++版：

class ValidWordAbbr {
public:
    ValidWordAbbr(vector<string> &dictionary) {
        for(auto i : dictionary) {
            string key = i[0] + to_string(i.length() - 2) + i[i.length() - 1];
            if(d.find(key) == d.end()) {
                vector<string> list;
                list.push_back(i);
                d.insert(pair<string, vector<string>>(key, list));
            } else {
                d[key].push_back(i);
            }
        }
    }

    bool isUnique(string word) {
        string key = word[0] + to_string(word.length() - 2) + word[word.length() - 1];
        if(d.find(key) == d.end())
            return true;
        else if(d[key].size() == 1 && d[key][0] == word)
            return true;
        return false;
    }
    
private:
    unordered_map<string, vector<string>> d;
};


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

Java版：

public class ValidWordAbbr {

    public ValidWordAbbr(String[] dictionary) {
        for(String s: dictionary) {
            String key = s.charAt(0) + Integer.toString(s.length() - 2) + s.charAt(s.length() - 1);
            if(d.containsKey(key)) {
                d.get(key).add(s);
            } else {
                List<String> l = new ArrayList<>();
                l.add(s);
                d.put(key, l);
            }
        }
    }

    public boolean isUnique(String word) {
        String key = word.charAt(0) + Integer.toString(word.length() - 2) + word.charAt(word.length() - 1);
        if(!d.containsKey(key))
            return true;
        else if(d.get(key).size() < 2  && d.get(key).get(0).equals(word))
            return true;
        return false;
    }
    
    private HashMap<String, List<String>> d = new HashMap<>();
}


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

Python版：

class ValidWordAbbr(object):
    def __init__(self, dictionary):
        """
        initialize your data structure here.
        :type dictionary: List[str]
        """
        self.d = collections.defaultdict(list)
        for i in dictionary:
            self.d[i[0] + str(len(i) - 2) + i[-1]].append(i)

    def isUnique(self, word):
        """
        check if a word is unique.
        :type word: str
        :rtype: bool
        """
        key = word[0] + str(len(word) - 2) + word[-1]
        if key not in self.d:
            return True
        elif len(self.d[key]) == 1 and self.d[key][0] == word:
            return True
        else:
            return False


# Your ValidWordAbbr object will be instantiated and called as such:
# vwa = ValidWordAbbr(dictionary)
# vwa.isUnique("word")
# vwa.isUnique("anotherWord")