1  2  9 10 25 26
 4  3  8 11 24 27
 5  6  7 12 23 28
16 15 14 13 22 29
17 18 19 20 21 30
36 35 34 33 32 31

public class Hello {
 
     public static void main(String[] args) {
         final int N = 6;
         for(int i = 0; i < N; i++) {
             for(int j = 0, m = 0; j < N; j++) {
                 if(j >= i) {
                     boolean b = j % 2 == 0;
                     m = (b ? (j + 1) * (j + 1) : j * j + 1) + (b ? -i : i);
                 } else {
                     boolean b = i % 2 == 0;
                     m = (b ? i * i + 1 : (i + 1) * (i + 1)) + (b ? j : -j);
                 }
                 System.out.printf("%2d ", m);
             }
             System.out.println();
         }
    }
}

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class PasswordTest {    

    private final static Matcher passwordMatcher = Pattern.compile(
            "^(?:([a-z])|([A-Z])|([0-9])|([@#$%])){8,15}$"
        ).matcher("");

    public static void main(String[] args) {

        String[] strs = {
                "abcdefg12345",
                "aaabbbAAA$$$",
                "aaabbbAAAa@13434",
                "aaAA11",
                "AAAaaa113@"
            };        

        for(int i = 0; i < strs.length; i++) {
            System.out.printf("str: %-20s  length: %2d  result: %s%n",
                    strs[i],
                    strs[i].length(),
                    checkPassword(strs[i])
                );
        }
    }    

    public static boolean checkPassword(String password) {

        if (password == null) {
            return false;
        }

        passwordMatcher.reset(password);

        if (!passwordMatcher.matches()) {
            return false;
        }

        int count = 0;
        for (int i = passwordMatcher.groupCount(); i > 0; i--) {
            if (passwordMatcher.start(i) > -1) {
                count++;
            }
        }
        return (count >= 3);
    }
}