Coding Problem (Strings)

problems-strings-20170511-1.java

    static int getMaxStrLen(String s) {
        Set<Character> chars = new HashSet<> ();
        char[] cArray = s.toCharArray();
        for (char c : cArray) {
            if (!chars.contains(c)) {
                chars.add(c);
            }
        }
        if (chars.size() < 2)
            return 0;

        Character[] chrArray =  chars.toArray(new Character[0]);
        StringBuilder sb = new StringBuilder();
        int maxLength = 0;

        for (int i=0; i<chrArray.length; i++) {
            for (int j = 1; j<chrArray.length; j++) {
                for (char c : cArray) {
                    if (c == chrArray[i] || c == chrArray[j])
                        sb.append(c);
                }
                String s2 = sb.toString();
                if (isValidString(s2)) {
                    if (s2.length() > maxLength)
                        maxLength = s2.length();
                }
                sb.setLength(0);
            }
        }
        return maxLength;
    }

    static boolean isValidString(String s) {
        if (s.length() < 2)
            return false;

        for (int i = 0; i < s.length() - 1; i++) {
            if (s.charAt(i) == s.charAt(i + 1))
                return false;
        }
        return true;
    }