804

804. Unique Morse Code Words (Easy)

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:

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

Given an array of strings words where 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 of "-.-.", ".-", and "-...". We will call such a concatenation the transformation of a word.

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

 

Example 1:

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 "--...--.".

Example 2:

Input: words = ["a"]
Output: 1

 

Constraints:

• 1 <= words.length <= 100
• 1 <= words[i].length <= 12
• words[i] consists of lowercase English letters.

Related Topics:
Array, Hash Table, String

Solution 1.

// OJ: https://leetcode.com/problems/unique-morse-code-words/
// Author: github.com/lzl124631x
// Time: O(N)
// Space: O(N)
class Solution {
private:
    string dict[26] = {".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--.."};
public:
    int uniqueMorseRepresentations(vector<string>& words) {
        unordered_set<string> s;
        for (string word : words) {
            string code;
            for (char c : word) code += dict[c - 'a'];
            s.insert(code);
        }
        return s.size();
    }
};