C++小程序——Unique Morse Code Words（ 莫尔斯电码）

Description:

International Morse Code defines a standard encoding where each letter is mapped to a series of dots and dashes, as follows: "a"maps to ".-", "b" maps to "-...", "c" maps to "-.-.", and so on.

For convenience, the full table for the 26 letters of the English alphabet is given below:

[".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--.."]

Now, given a list of words, each word can be written as a concatenation of the Morse code of each letter. For example, "cab" can be written as "-.-.-....-", (which is the concatenation "-.-." + "-..." + ".-"). We'll call such a concatenation, the transformation of a word.

Return the number of different transformations among all words we have.

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 "--...--.".

 

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.

Solution 1:

class Solution {
public:
    int uniqueMorseRepresentations(vector<string>& words) {
    const vector<string> letters = { ".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--.." };
	set<string> str_set;
        string s;
        for (const auto &word : words) {
            s = "";
            for (const auto &ch : word) {
                s.append(letters[ch-'a']);
            }
            str_set.insert(s);
        }
        return str_set.size();
    }
};

Solution 2:

class Solution {
public:
    int uniqueMorseRepresentations(vector<string>& words) {
    const vector<string> letters = { ".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--.." };
	int count = 0;
	set<string> temp;
	string s;

	for (int i = 0; i<words.size(); i++)
	{
		for (int j = 0; j<words[i].size(); j++)
		{
			s.append(letters[(words[i])[j] - 'a']);
		}
		temp.insert(s);
		s = "";
	 } 	
	count = temp.size();
	return count;
    }
};

Solution 3:

class Solution {
public:
    int uniqueMorseRepresentations(vector<string>& words) {
        string ws[] = {".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--.."};
    set<string> a;
    for(string n:words){
        string t="";
        for(int i=0;i<n.size();i++){
            string tn = ws[(int)(n[i])-97];
          t+=tn;
        }
        a.insert(t);
    }
    return a.size();
    }
};