[LeetCode] 804. Unique Morse Code Words-优快云博客

题目描述：

a-z都有对应的莫斯密码
为：
[“.-“,”-…”,”-.-.”,”-..”,”.”,”..-.”,”–.”,”….”,”..”,”.—”,”-.-“,”.-..”,”–”,”-.”,”—”,”.–.”,”–.-“,”.-.”,”…”,”-“,”..-“,”…-“,”.–”,”-..-“,”-.–”,”–..”]

Example:
Input: words = ["gin", "zen", "gig", "msg"]
Output: 2
Explanation: 
The transformation of each word is:
"gin" -> "--...-."
"zen" -> "--...-."
"gig" -> "--...--."
"msg" -> "--...--."

There are 2 different transformations, "--...-." and "--...--.".

即找到这个words中使用变换得到不同的莫斯密码。

Note:

    The length of words will be at most 100.
    Each words[i] will have length in range [1, 12].
    words[i] will only consist of lowercase letters.

最佳实践：
对words中每一个string中都转为莫斯密码，放入c++的标准库中的unordered_set容器中，此处注意是无序容器，对于无序容器，由于无需维护元素的顺序，故效率比set容器高。无序容器是用Hash函数进行对关键字的组织的，底层数据结构为红黑树。

class Solution {
public:
    vector<string> code={".-","-...","-.-.","-..",".",
                         "..-.","--.","....","..",".---",
                         "-.-",".-..","--","-.","---",".--.",
                         "--.-",".-.","...","-","..-","...-",
                         ".--","-..-","-.--","--.."};
    int uniqueMorseRepresentations(vector<string>& words) 
    {
        int res = 0;
        unordered_set<string> unique_code;
        for(const auto &i:words)
        {
            string wordcode;
            for(auto c:i)
            {
                wordcode += code[c-'a'];
            }
            unique_code.insert(wordcode);
        }
        return unique_code.size();

    }
};