leetcode(4) uniqueMorseCodeWords

difficult：easy #804

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.

解法1:

#include<string>
#include<vector>
#include<set>
int uniqueMorseRepresentations(std::vector<std::string>& words) {
	std::vector<std::string> morse = { ".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--.." };
	std::set<std::string> seen;
	for(std::string word:words){
		std::string code;
		for(char c : word){
			code.append(morse[c - 'a']);//'a'->97
		}
		seen.insert(code);
	}
	return seen.size();
}

解法2：

#include<map>
#include<string>
#include<vector>
int uniqueMorseRepresentations(std::vector<std::string>& words) {
	std::string alpha = "abcdefghijklmnopqrstuvwxyz";
	std::vector<std::string> morse = { ".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--.." };
	std::map<char, std::string> alpha_code;
	int index = 0;
	for (auto i = alpha.begin(); i < alpha.end(); i++) {
		alpha_code[*i] = morse[index++];
	}
	std::set<std::string> seen;
	for (std::string str : words) {
		std::string str_code;
		for (char c : str) {
			str_code += alpha_code[c];
		}
		seen.insert(str_code);
	}
	return seen.size();
}

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