Blogs Hub

Unique Morse Code Words - MiniTV

Unique Morse Code Words - मिनी टीवी

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.

 

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.

 

Solution:

using System;
using System.Collections.Generic;
using System.Text;

namespace NetCoreCoding.LeetCode.String.Easy
{
    public class UniqueMorseRepresentationsSoln
    {
        public UniqueMorseRepresentationsSoln()
        {
        }

        public void execute()
        {
            var words = new string[] { "gin", "zen", "gig", "msg" };
            var res = UniqueMorseRepresentations(words);
            Assert(res, 2);
        }

        private void Assert(int response, int expected)
        {
            if (response != expected)
                throw new Exception("Incorrect Answer.");
        }

        public int UniqueMorseRepresentations(string[] words)
        {
            var morse = new string[] { ".-", "-...", "-.-.", "-..", ".", "..-.", "--.", "....", "..", ".---", "-.-", ".-..", "--", "-.", "---", ".--.", "--.-", ".-.", "...", "-", "..-", "...-", ".--", "-..-", "-.--", "--.." };
            var set = new HashSet<string>();
            foreach (var word in words)
            {
                var str = new StringBuilder();
                for (int i = 0; i < word.Length; i++)
                {
                    str.Append(morse[word[i]-'a']);
                }
                set.Add(str.ToString().Trim());
            }

            return set.Count;
        }
    }
}

 

Time Complexity: O(n^2)

Space Complexity: O(n)