Huffman decoding

Author: ProgrammingLanguageLeader

src/algorithms/huffman_coding/decoding/Main.java

@@ -0,0 +1,44 @@
+package algorithms.huffman_coding.decoding;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Scanner;
+
+public class Main {
+    private void run() {
+        Scanner scanner = new Scanner(System.in);
+        int differentSymbolsNumber = scanner.nextInt();
+        int encodedMessageLength = scanner.nextInt();
+        Map<String, Character> decodingTable = new HashMap<>();
+        for (int i = 0; i < differentSymbolsNumber; i++) {
+            char symbol = scanner.next().charAt(0);
+            String code = scanner.next();
+            decodingTable.put(code, symbol);
+        }
+        String encodedMessage = scanner.next();
+        if (encodedMessage.length() > encodedMessageLength) {
+            encodedMessage = encodedMessage.substring(0, encodedMessageLength - 1);
+        }
+
+        String decodedMessage = decodeMessage(encodedMessage, decodingTable);
+        System.out.println(decodedMessage);
+    }
+
+    private String decodeMessage(String encodedMessage, Map<String, Character> decodingTable) {
+        StringBuilder decodedMessageBuilder = new StringBuilder();
+        StringBuilder currentCodeBuilder = new StringBuilder();
+        for (int i = 0; i < encodedMessage.length(); i++) {
+            currentCodeBuilder.append(encodedMessage.charAt(i));
+            Character symbol = decodingTable.get(currentCodeBuilder.toString());
+            if (symbol != null) {
+                decodedMessageBuilder.append(symbol);
+                currentCodeBuilder.setLength(0);
+            }
+        }
+        return decodedMessageBuilder.toString();
+    }
+
+    public static void main(String[] args) {
+        new Main().run();
+    }
+}