HDU 5050 Divided Land ( JAVA )

import java.io.*;
import java.math.BigInteger;
import java.util.*;

public class Main {
    static PrintWriter out = new PrintWriter(new BufferedWriter(
            new OutputStreamWriter(System.out)));

    public static void main(String[] args) throws IOException {
        Scan scan = new Scan();
        int t = scan.nextInt();
        for (int c = 1; c <= t; c++) {
            String s = scan.next();
            BigInteger a = new BigInteger(s,2);
            s = scan.next();
            BigInteger b = new BigInteger(s,2);
            out.println("Case #" + c + ": " + a.gcd(b).toString(2));
        }
        out.flush();
    }

    private static double max(double d, double e) {
        if (d - e > 0)
            return d;
        return e;
    }
}

class Scan {

    BufferedReader buffer;
    StringTokenizer tok;

    Scan() {
        buffer = new BufferedReader(new InputStreamReader(System.in));
    }

    boolean hasNext() {
        while (tok == null || !tok.hasMoreElements()) {
            try {
                tok = new StringTokenizer(buffer.readLine());
            } catch (Exception e) {
                return false;
            }
        }
        return true;
    }

    String next() {
        if (hasNext())
            return tok.nextToken();
        return null;
    }

    String nextLine() {
        String s = null;
        try {
            s = buffer.readLine();
        } catch (Exception e) {
            return null;
        }
        return s;
    }

    char nextChar() {
        try {
            return ((char) buffer.read());
        } catch (Exception e) {
        }
        return ‘\0‘;
    }

    int nextInt() {
        return Integer.parseInt(next());
    }

    long nextLong() {
        return Long.parseLong(next());
    }

    double nextDouble() {
        return Double.parseDouble(next());
    }
}