# 804. Unique Morse Code Words

## 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:

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

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.

## Solutions

• class Solution {
public int uniqueMorseRepresentations(String[] words) {
String[] codes = new String[] {".-", "-...", "-.-.", "-..", ".", "..-.", "--.", "....",
"..", ".---", "-.-", ".-..", "--", "-.", "---", ".--.", "--.-", ".-.", "...", "-",
"..-", "...-", ".--", "-..-", "-.--", "--.."};
Set<String> s = new HashSet<>();
for (String word : words) {
StringBuilder t = new StringBuilder();
for (char c : word.toCharArray()) {
t.append(codes[c - 'a']);
}
}
return s.size();
}
}

• class Solution {
public:
int uniqueMorseRepresentations(vector<string>& words) {
vector<string> codes = {".-", "-...", "-.-.", "-..", ".", "..-.", "--.", "....", "..", ".---", "-.-", ".-..", "--", "-.",
"---", ".--.", "--.-", ".-.", "...", "-", "..-", "...-", ".--", "-..-", "-.--", "--.."};
unordered_set<string> s;
for (auto& word : words) {
string t;
for (char& c : word) t += codes[c - 'a'];
s.insert(t);
}
return s.size();
}
};

• class Solution:
def uniqueMorseRepresentations(self, words: List[str]) -> int:
codes = [
".-",
"-...",
"-.-.",
"-..",
".",
"..-.",
"--.",
"....",
"..",
".---",
"-.-",
".-..",
"--",
"-.",
"---",
".--.",
"--.-",
".-.",
"...",
"-",
"..-",
"...-",
".--",
"-..-",
"-.--",
"--..",
]
s = {''.join([codes[ord(c) - ord('a')] for c in word]) for word in words}
return len(s)


• func uniqueMorseRepresentations(words []string) int {
codes := []string{".-", "-...", "-.-.", "-..", ".", "..-.", "--.", "....", "..", ".---", "-.-", ".-..", "--", "-.",
"---", ".--.", "--.-", ".-.", "...", "-", "..-", "...-", ".--", "-..-", "-.--", "--.."}
s := make(map[string]bool)
for _, word := range words {
t := &strings.Builder{}
for _, c := range word {
t.WriteString(codes[c-'a'])
}
s[t.String()] = true
}
return len(s)
}

• const codes = [
'.-',
'-...',
'-.-.',
'-..',
'.',
'..-.',
'--.',
'....',
'..',
'.---',
'-.-',
'.-..',
'--',
'-.',
'---',
'.--.',
'--.-',
'.-.',
'...',
'-',
'..-',
'...-',
'.--',
'-..-',
'-.--',
'--..',
];

function uniqueMorseRepresentations(words: string[]): number {
return new Set(
words.map(word => {
return word
.split('')
.map(c => codes[c.charCodeAt(0) - 'a'.charCodeAt(0)])
.join('');
}),
).size;
}


• use std::collections::HashSet;
impl Solution {
pub fn unique_morse_representations(words: Vec<String>) -> i32 {
const codes: [&str; 26] = [
".-",
"-...",
"-.-.",
"-..",
".",
"..-.",
"--.",
"....",
"..",
".---",
"-.-",
".-..",
"--",
"-.",
"---",
".--.",
"--.-",
".-.",
"...",
"-",
"..-",
"...-",
".--",
"-..-",
"-.--",
"--..",
];
words
.iter()
.map(|word| {
word.as_bytes()
.iter()
.map(|v| codes[(v - b'a') as usize])
.collect::<String>()
})
.collect::<HashSet<String>>()
.len() as i32
}
}