ctf.java

package com.company;

import java.lang.reflect.Array;
import java.security.MessageDigest;
import java.util.*;

public class Main {

    public static void main(String[] args) {
        List<Cell> todas = new ArrayList<Cell>();
        todas.add(new Cell(0, 0));
        todas.add(new Cell(1, 0));
        todas.add(new Cell(2, 0));
        todas.add(new Cell(0, 1));
        todas.add(new Cell(1, 1));
        todas.add(new Cell(2, 1));
        todas.add(new Cell(0, 2));
        todas.add(new Cell(1, 2));
        todas.add(new Cell(2, 2));

        int size = 8;
        byte[] origin = new byte[size];

        for(;;)
        {
            List<Cell> celdas = getNextCombination(todas, origin, size);
            if(celdas == null)
            {
                break;
            }
            String resultado = patternToString(celdas);
            if (resultado.substring(0, 10).equals("6145494400"))
            {
                for(int i=0;i<size;i++)
                {
                    System.out.println(celdas.get(i).getRow() + ", " +  celdas.get(i).getColumn());
                }
            }
        }
    }

    private static List<Cell> getNextCombination(List<Cell> todas, byte[] origin, int size)
    {
        origin[size-1]++;
        for(int i=size-1;i>=0;i--)
        {
            if(origin[i] > 8)
            {
                if(i == 0)
                {
                    return null;
                }
                origin[i] = 0;
                origin[i-1]++;
            }
        }

        ArrayList<Cell> list = new ArrayList<Cell>(size);
        for(int i=0;i<size;i++)
        {
            list.add(todas.get(origin[i]));
        }

        return list;
    }

    public static byte[] patternToByteArray(final List<Cell> list) {
        byte[] array;
        if (list == null) {
            array = null;
        }
        else {
            final int size = list.size();
            final byte[] array2 = new byte[size];
            int n = 0;
            while (true) {
                array = array2;
                if (n >= size) {
                    break;
                }
                final Cell cell = list.get(n);
                array2[n] = (byte)(cell.getRow() * 3 + cell.getColumn());
                ++n;
            }
        }
        return array;
    }

    public static String byteArrayToHexString(final byte[] array) {
        String string = "";
        for (int i = 0; i < array.length; ++i) {
            string = String.valueOf(string) + Integer.toString((array[i] & 0xFF) + 256, 16).substring(1);
        }
        return string;
    }

    public static String patternToString(final List<Cell> list) {
        final byte[] patternToByteArray = patternToByteArray(list);
        if (patternToByteArray == null) {
            return "";
        }
        try {
            return byteArrayToHexString(MessageDigest.getInstance("SHA-1").digest(patternToByteArray));
        }
        catch (Exception ex) {
            return "";
        }
    }

    private static class Cell
    {
        private int row;
        private int column;

        public Cell(int row, int column)
        {
            this.row = row;
            this.column = column;
        }

        public int getRow()
        {
            return row;
        }

        public int getColumn()
        {
            return column;
        }
    }
}