(SPOJ) 2280 - Encontre o telefone - Solução 1

Solução mais eficiente.

import java.io.*;
import java.util.*;

class Main {
    public static void main(String[] args) throws NumberFormatException, IOException {
        Main processando = new Main();
        processando.processa();
       
        System.exit(0);
    }
   
    void processa() throws NumberFormatException, IOException {
        int[] vetor = new int[91];
       
        vetor[(int)'A'] = '2';
        vetor[(int)'B'] = '2';
        vetor[(int)'C'] = '2';
        vetor[(int)'D'] = '3';
        vetor[(int)'E'] = '3';
        vetor[(int)'F'] = '3';
        vetor[(int)'G'] = '4';
        vetor[(int)'H'] = '4';
        vetor[(int)'I'] = '4';
        vetor[(int)'J'] = '5';
        vetor[(int)'K'] = '5';
        vetor[(int)'L'] = '5';
        vetor[(int)'M'] = '6';
        vetor[(int)'N'] = '6';
        vetor[(int)'O'] = '6';
        vetor[(int)'P'] = '7';
        vetor[(int)'Q'] = '7';
        vetor[(int)'R'] = '7';
        vetor[(int)'S'] = '7';
        vetor[(int)'T'] = '8';
        vetor[(int)'U'] = '8';
        vetor[(int)'V'] = '8';
        vetor[(int)'X'] = '9';
        vetor[(int)'Y'] = '9';
        vetor[(int)'W'] = '9';
        vetor[(int)'Z'] = '9';
        vetor[(int)'0'] = '0';
        vetor[(int)'1'] = '1';
        vetor[(int)'-'] = '-';
       
        String line = "";
       
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
             
        while((line = br.readLine()) != null) {
            for (int i = 0; i < line.length(); i++) {
                bw.write(vetor[(int)line.charAt(i)]);
            }

            bw.write("\n");
        }

        bw.flush();
        bw.close();                   
        return;
    }
}