fork(1) download
copy 
  1. import java.util.List;
  2. import java.math.BigInteger;
  3. import java.util.ArrayList;
  4. import java.util.Collections;
  5.  
  6. /**
  7.  * @author Victor
  8.  */
  9. public class Main {
  10.  
  11.     public static void main(String[] args) {
  12.         // Passa o alfabeto como parâmetro. Tem 62 caracteres aqui, então são 62 símbolos.
  13.         BaseN bn = new BaseN("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz");
  14.         String x = "The quick brown fox jumps over a lazy dog";
  15.         System.out.println(x);
  16.         String a = bn.encode(x);
  17.         System.out.println(a); // Escreve "1u9WLfG65OMtVkQWPtWDcC6o8IjI5td5l9DzpilIK4Nyx81tKLRrStPj"
  18.         String b = bn.decode(a);
  19.         System.out.println(b); // Escreve "The quick brown fox jumps over a lazy dog"
  20.     }
  21. }
  22.  
  23. class BaseN {
  24.     private static final BigInteger BI_256 = BigInteger.valueOf(256);
  25.  
  26.     private final String base;
  27.     private final BigInteger radix;
  28.  
  29.     public BaseN(String base) {
  30.         this.base = base;
  31.         this.radix = BigInteger.valueOf(base.length());
  32.     }
  33.  
  34.     public String encode(String text) {
  35.         byte[] bytes = text.getBytes();
  36.         BigInteger big = BigInteger.ONE;
  37.         for (byte b : bytes) {
  38.             big = big.multiply(BI_256).add(BigInteger.valueOf(b));
  39.         }
  40.         StringBuilder sb = new StringBuilder(bytes.length * 4 / 3 + 2);
  41.         while (!BigInteger.ZERO.equals(big)) {
  42.             BigInteger[] parts = big.divideAndRemainder(radix);
  43.             int small = parts[1].intValue();
  44.             big = parts[0];
  45.             sb.append(base.charAt(small));
  46.         }
  47.  
  48.         return sb.reverse().toString();
  49.     }
  50.  
  51.     public String decode(String text) {
  52.         BigInteger big = BigInteger.ZERO;
  53.         for (char c : text.toCharArray()) {
  54.             int i = base.indexOf(c);
  55.             if (i == -1) throw new IllegalArgumentException();
  56.             big = big.multiply(radix).add(BigInteger.valueOf(i));
  57.         }
  58.  
  59.         List<Byte> byteList = new ArrayList<>(text.length());
  60.         while (!BigInteger.ZERO.equals(big)) {
  61.             BigInteger[] parts = big.divideAndRemainder(BI_256);
  62.             int small = parts[1].intValue();
  63.             big = parts[0];
  64.             byteList.add((byte) small);
  65.         }
  66.         Collections.reverse(byteList);
  67.  
  68.         byte[] r = new byte[byteList.size() - 1];
  69.         int i = 0;
  70.         for (Byte b : byteList) {
  71.             if (i > 0) r[i - 1] = b;
  72.             i++;
  73.         }
  74.         return new String(r);
  75.     }
  76. }
Success #stdin #stdout 0.07s 380160KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
The quick brown fox jumps over a lazy dog
1u9WLfG65OMtVkQWPtWDcC6o8IjI5td5l9DzpilIK4Nyx81tKLRrStPj
The quick brown fox jumps over a lazy dog
https://ideone.com/KDMyH7
language:
Java (12.0.1)
created:
9 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!