Add solution #804

Author: JoshCrozier

solutions/0804-unique-morse-code-words.js

@@ -0,0 +1,39 @@
+/**
+ * 804. Unique Morse Code Words
+ * https://leetcode.com/problems/unique-morse-code-words/
+ * Difficulty: 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:
+ *
+ * [".-","-...","-.-.","-..",".","..-.","--.","....","..",
+ * ".---","-.-",".-..","--","-.","---",".--.","--.-",".-.",
+ * "...","-","..-","...-",".--","-..-","-.--","--.."]
+ *
+ * Now, given a list of words, each word can be written as a
+ * concatenation of the Morse code of each letter.
+ * For example, "cba" 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.
+ */
+
+/**
+ * @param {string[]} words
+ * @return {number}
+ */
+var uniqueMorseRepresentations = function(words) {
+  const codes = [".-","-...","-.-.","-..",".","..-.","--.","....","..",".---",
+                 "-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-",
+                 "..-","...-",".--","-..-","-.--","--.."];
+  const map = new Map(codes.map((v, i) => [String.fromCharCode(97 + i), v]));
+  const transformed = words.map(word => word.split('').map(c => map.get(c)).join(''));
+  return new Set(transformed).size;
+};