804. Unique Morse code word

Title Description

The International Morse code defines a standard encoding method , Each letter corresponds to a string of dots and dashes , such as : “a” Corresponding “.-”, “b” Corresponding “-…”, “c” Corresponding “-.-.”, wait .

For convenience , all 26 The English letters correspond to Morse code table as follows ：

[".-","-…","-.-.","-…",".","…-.","–.","…","…",".—","-.-",".-…","–","-.","—",".–.","–.-",".-.","…","-","…-","…-",".–","-…-","-.–","–…"]
Given a list of words , Each word can be written as a combination of each letter corresponding to the Morse code . for example ,“cab” It can be written. “-.-…–…”,( namely “-.-.” + “-…” + ".-" A combination of strings ). We call this linking process word translation .

Back, we can get the number of different word translations of all words .
https://leetcode-cn.com/problems/unique-morse-code-words/

for example :
Input : words = [“gin”, “zen”, “gig”, “msg”]
Output : 2
explain :
The words are translated as follows :
“gin” -> “–…-.”
“zen” -> “–…-.”
“gig” -> “–…--.”
“msg” -> “–…--.”

share 2 There are two different translations , “–…-.” and “–…--.”.

Their thinking

First traversal words Array , And then I'm going to go through each one word The word gets the corresponding string in the password table according to the letters, and finally adds .
You can subtract... According to the obtained letters 97（'a’ Of ASCII code ） Get the corresponding password . The last is weight removal , It can be used Set Realization .

Code implementation

// 68 ms 36 MB
/** * @param {string[]} words * @return {number} */
var uniqueMorseRepresentations = function(words) {
    
  let arr = [".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--.."]
  let res=new Set();
  words.forEach(item=>{
    
    let word='';
    for(let k of item){
    
      word+=arr[k.charCodeAt()-'a'.charCodeAt()];
    }
    res.add(word);
  })
  return res.size;
};