[LeetCode288]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
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刚开始觉得就是找出abbreviation当key 把自己加到hashtable里，然后看每个key的size是不是1就可以判断是不是unique word了，但是发现了这句话

A word's abbreviation is unique if no other word from the dictionary has the same abbreviation.

就比如a，a，a自己的缩写和自己一样，也算unique的。

有两种structure可以用，vector 和set。

class ValidWordAbbr {
public:
ValidWordAbbr(vector<string> &dictionary) {
for(string s : dictionary){
mp[abbrivate(s)].push_back(s);
}
}
string abbrivate(string s){
int len = s.size();
return len<=2 ? s : s[0] + to_string(len-2) + s[len-1];
}
bool isUnique(string word) {
for(string s : mp[abbrivate(word)]){
if(s != word) return false;
}
return true;
}
private: unordered_map<string, vector<string>> mp;
// Your ValidWordAbbr object will be instantiated and called as such:
// ValidWordAbbr vwa(dictionary);
// vwa.isUnique("hello");
// vwa.isUnique("anotherWord");
};

class ValidWordAbbr {
public:
ValidWordAbbr(vector<string> &dictionary) {
for(string s : dictionary){
mp[abbrivate(s)].push_back(s);
}
}
string abbrivate(string s){
int len = s.size();
return len<=2 ? s : s[0] + to_string(len-2) + s[len-1];
}
bool isUnique(string word) {
return (mp[abbrivate(word)].size() == 1 && mp[abbrivate(word)].find(word) != mp[abbrivate(word)].end()) || mp[abbrivate(word)].empty();
}
private: unordered_map<string, unordered_set<string>> mp;
// Your ValidWordAbbr object will be instantiated and called as such:
// ValidWordAbbr vwa(dictionary);
// vwa.isUnique("hello");
// vwa.isUnique("anotherWord");
};