Morse code is a method used in telecommunication to encode text characters as standardized sequences of two different signal durations, called dots and dashes. 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:
Table:
[".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---", ".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--.."]
1. To convert the given English letter to Morse Code and vice versa using iteration
Example:
Input: geeks Output: --. . . -.- ... Explanation: Here each letter in string is converted into morse code given at Table like for g letter morse code is "--." ,e=".",e=".",k="-.-",s="..." Input: school Output: ... -.-. .... --- --- .-..
Approach:
- Store all the alphabet in an array named in this code is letter[] same here store all the alphabet in another array named code[].
- Convert the input string to char array str[].
- Iteratively match the character position with a letter in the letter array.
- Find its character position in that letter[] array and using that position returns the character present at that position from the code[] array.
- Iteratively find all Morse Code for all character in an input string and vice versa.
Below is the implementation of the above approach.
Java
// Java Program to Convert English// Text to Morse Code and Vice Versaimport java.util.*;public class Main { public static void morseToEnglish(String[] code, String morseCode) { String[] array = morseCode.split(" "); System.out.print("Morse code " + morseCode + " to English is "); // Morse code to English for (int i = 0; i < array.length; i++) { for (int j = 0; j < code.length; j++) { if (array[i].compareTo(code[j]) == 0) { System.out.print((char)(j + 'a') + " "); break; } } } } public static void englishToMorse(String[] code, String englishLang, char[] letter) { System.out.print("Morse code of " + englishLang + " is "); for (int i = 0; i < englishLang.length(); i++) { for (int j = 0; j < letter.length; j++) { if (englishLang.charAt(i) == letter[j]) { System.out.print(code[j] + " "); break; } } } } public static void main(String[] args) { // store the all the alphabet in an array char[] letter = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0' }; // Morse code by indexing String[] code = { ".-", "-...", "-.-.", "-..", ".", "..-.", "--.", "....", "..", ".---", "-.-", ".-..", "--", "-.", "---", ".--.", "--.-", ".-.", "...", "-", "..-", "...-", ".--", "-..-", "-.--", "--..", "|" }; // Given Strings String morseCode = "... -.-. .... --- --- .-.."; String englishLang = "alice"; // morse to English morseToEnglish(code, morseCode); System.out.println(); // English to morse code englishToMorse(code, englishLang, letter); }} |
Output
Morse code ... -.-. .... --- --- .-.. to English is s c h o o l Morse code of alice is .- .-.. .. -.-. .
- Time Complexity: O(n2)
- Space Complexity: O(1)
2. Conversion using HashMap
Example:
Input: ... -.-. .... --- --- .-.. Output: school Explanation: Just reverse the step of previous one "..."=>s, "-.-"=>c, "...."=>h, "---"=>o, "---"=>o, ".-.."=> l Input: --. . . -.- ... Output: geeks
Approach:
A. Morse Code to English.
- Create two maps for Morse code to English conversion.
- Push all the Morse code and respective alphabets in the map.
- Start traversing Morse code string and display its respective English alphabet.
B. English to Morse Code.
- Store Morse code in the array.
- Start traversing string of English sentences.
- Use expression englishCharacter-‘a’ to get an index of Morse code.
Below is an implementation of the above approach
Java
// Java Program to Convert English// Text to Morse Code and Vice Versaimport java.util.*;public class Main { public static void morseToEnglish(String[] code, String morseCode) { // morse code to English Hashmap Map<String, Character> morseToEnglish = new HashMap<>(); // Map value allocation for (int i = 0; i < 26; i++) { morseToEnglish.put(code[i], (char)('a' + i)); } // Split morse code in array of string String[] array = morseCode.split(" "); System.out.print("Morse code " + morseCode + " to English is "); // Morse code to English for (int i = 0; i < array.length; i++) { System.out.print(morseToEnglish.get(array[i]) + " "); } } public static void englishToMorse(String[] code, String englishLang) { for (int i = 0; i < englishLang.length(); i++) { System.out.print( code[englishLang.charAt(i) - 'a'] + " "); } } public static void main(String[] args) { // Morse code by indexing String[] code = { ".-", "-...", "-.-.", "-..", ".", "..-.", "--.", "....", "..", ".---", "-.-", ".-..", "--", "-.", "---", ".--.", "--.-", ".-.", "...", "-", "..-", "...-", ".--", "-..-", "-.--", "--..", "|" }; // Given Strings String morseCode = "... -.-. .... --- --- .-.."; String englishLang = "alice"; // morse to English morseToEnglish(code, morseCode); System.out.println(); // English to morse code englishToMorse(code, englishLang); }} |
Output
Morse code ... -.-. .... --- --- .-.. to English is s c h o o l .- .-.. .. -.-. .
- Time Complexity: O(n)
- Space Complexity: O(n)
