UVA - 444 - Encoder and Decoder

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) throws IOException {
        InputStreamReader isr=new InputStreamReader(System.in);
        BufferedReader br=new BufferedReader(isr);
        StringBuffer sb = new StringBuffer("");
        String m = "";
        while ((m=br.readLine())!=null) {
            if (m.equals("")) {
                sb.append("\n");
                continue;
            }
            StringBuilder temp = new StringBuilder("");
            if (m.charAt(0) >= '0' && m.charAt(0) <= '9') {
                m = new StringBuilder(m).reverse().toString();
                for (int i = 0; i < m.length();) {
                    StringBuilder temp2 = new StringBuilder("");
                    if (m.charAt(i) == '1') {
                        temp2.append(m.charAt(i)).append(m.charAt(i + 1)).append(m.charAt(i + 2));
                        i += 3;
                    } else {
                        temp2.append(m.charAt(i)).append(m.charAt(i + 1));
                        i += 2;
                    }
                    char c = (char) Integer.parseInt(temp2.toString());
                    temp.append((char)c);
                }
            } else {
                for (int i = 0; i < m.length(); i++) {
                    if (m.charAt(i) == 32 || m.charAt(i) == 33 || m.charAt(i) == 44 || m.charAt(i) == 46
                            || m.charAt(i) == 58 || m.charAt(i) == 59 || m.charAt(i) == 63) {
                        temp.append((int) m.charAt(i));
                    } else if (m.charAt(i) >= 'a' && m.charAt(i) <= 'z') {
                        temp.append((int) m.charAt(i));
                    } else if (m.charAt(i) >= 'A' && m.charAt(i) <= 'Z') {
                        temp.append((int) m.charAt(i));
                    }
                }
            }
            if (m.charAt(0) >= '0' && m.charAt(0) <= '9') {
                sb.append(temp);
            } else {
                sb.append(temp.reverse());
            }
            sb.append("\n");
        }
        System.out.print(sb);
    }
}