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  1. import java.lang.*;
  2. import java.util.*;
  3. import java.security.MessageDigest;
  4.  
  5. public class Collisions {
  6.   static int  N = 50;
  7.   static long M = (long)Math.pow(2, 32);
  8.  
  9.   public static void main(String[] args) {
  10.     Map<Long,Long> results = new HashMap<Long,Long>();
  11.  
  12.     while (true) {
  13.       long i = (long)Math.floor(Math.random() * M);
  14.       String message = Long.toString(i, 16);
  15.       long hash = lsbsha256(N, message);
  16.  
  17.       if (results.containsKey(hash) && results.get(hash) != i) {
  18.         System.out.println(String.format("%d: %s, %s",
  19.                                           hash,
  20.                                           Long.toString(results.get(hash), 16),
  21.                                           message));
  22.       } else {
  23.         results.put(hash, i);
  24.       }
  25.     }
  26.   }
  27.  
  28.   private static long lsbsha256(int n, String string) {
  29.     try {
  30.       MessageDigest md = MessageDigest.getInstance("SHA-256");
  31.       md.update(string.getBytes("UTF-8"));
  32.       byte[] bytes = md.digest();
  33.  
  34.       long hash = 0, mask = (long)Math.pow(2,n) - 1;
  35.       for (int i = 0; i * 8 <= n; i++) {
  36.         long b = (long)(bytes[bytes.length - 1 - i] & 0xFF);
  37.         hash = (hash | (b << (8 * i))) & mask;
  38.       }
  39.       return hash;
  40.  
  41.     } catch (java.security.NoSuchAlgorithmException e) {
  42.       return 0L;
  43.     } catch (java.io.UnsupportedEncodingException e) {
  44.       return 0L;
  45.     }
  46.   }
  47. }
  48.  
Compilation error #stdin compilation error #stdout 0s 0KB
comments ()
stdin 
03c08f4ee0b576fe319338139c045c89c3e8e9409633bea29442e21425006ea8
compilation info 
Main.java:5: error: class Collisions is public, should be declared in a file named Collisions.java
public class Collisions {
       ^
1 error
stdout 
Standard output is empty
https://ideone.com/mnoPqR
language:
Java (HotSpot 12)
created:
11 years ago
visibility:
public

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