I used dynamic programming for solving this problem, on the sample test program's output is correct, I have WA1 and do not know, were is the bug. Help me, please!

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class Solution implements Runnable {

    BufferedReader in;
    PrintWriter out;
    StringTokenizer strtok;

    int nextInt() throws Exception {
        while (strtok == null || !strtok.hasMoreTokens()) {
            strtok = new StringTokenizer(in.readLine());
        }
        return Integer.parseInt(strtok.nextToken());
    }

    int n;
    int[][] d;
    String[] c;
    int[][] pos = {{0, 1, 3, 2, 4, 5}, // stay on bottom
                  {0, 4, 3, 5, 1, 2},  // stay on left
                  {5, 1, 4, 2, 3, 0}};

    boolean match(int c1, int pos1, int c2, int pos2) {
        char[] s1 = new char[6], s2 = new char[6];
        for (int i = 0; i < 6; ++i) {
            s1[i] = c[c1].charAt(pos[pos1][i]);
            s2[i] = c[c2].charAt(pos[pos2][i]);
        }

        boolean ok1, ok2;
        for (int shift = 0; shift < 4; ++shift) {
            ok1 = true;
            ok2 = true;
            for (int i = 0; i < 4; ++i) {
                if (s1[i] != s2[(i + shift) % 4]) {
                    ok1 = false;
                    break;
                }
            }
            for (int i = 0; i < 4; ++i) {
                if (s1[3 - i] != s2[(i + shift) % 4]) {
                    ok2 = false;
                    break;
                }
            }
            if (ok1 || ok2) {
                return true;
            }
        }
        return false;
    }

    void solve() {
        d = new int[pos.length][n];
        for (int curbox = 0; curbox < n; ++curbox) {
            for (int curpos = 0; curpos < pos.length; ++curpos) {
                d[curpos][curbox] = 1;
                for (int prevbox = 0; prevbox < curbox; ++prevbox) {
                    for (int prevpos = 0; prevpos < pos.length; ++prevpos) {
                        if (match(prevbox, prevpos, curbox, curpos)) {
                            d[curpos][curbox] = Math.max(d[curpos][curbox], d[prevpos][prevbox] + 1);
                        }
                    }
                }
            }
        }
    }

    void outputDP() {
        for (int i = 0; i < pos.length; ++i) {
            for (int j = 0; j < n; ++j) {
                out.printf("%d ", d[i][j]);
            }
            out.println();
        }
    }

    public void run() {
        try {
            in = new BufferedReader(new InputStreamReader(System.in));
            out = new PrintWriter(System.out);

            n = nextInt();
            c = new String[n];
            for (int i = 0; i < n; ++i) {
                c[i] = in.readLine();
            }
            solve();
            //outputDP();

            int max = 0;
            for (int i = 0; i < pos.length; ++i) {
                max = Math.max(d[i][n - 1], max);
            }
            out.println(max);

            /*c = new String[2];
            c[0] = in.readLine();
            int aa = nextInt();
            c[1] = in.readLine();
            int bb = nextInt();
            out.println(match(0, aa, 1, bb));*/

        } catch (Exception er) {
            er.printStackTrace();
            System.exit(13);
        } finally {
            out.close();
        }
    }

    public static void main(String[] args) {
        new Thread(new Solution()).start();
    }
}

>I have WA1 and do not know, were is the bug

That was Timus bug. Old test#1 had a brick with 2 sides of the same color. Now test#1 is a sample test. You have TL now.

Thank you!