问带字符的最长字符串回文

EN

int maxL = 0;
    for (int i = 0; i < S.length(); i++) {
        String currentString = String.valueOf(S.charAt(i));
        for (int j = i + 1; j < S.length(); j = j + 1) {
            String jStr = String.valueOf(S.charAt(j));
            if (currentString.contains(jStr)) {
                currentString = currentString.replace(jStr, "");
                int len = j - i + 1;
                if (currentString.length() == 0 && maxL < len) {
                    maxL = len;
                }
            } else {
                currentString = currentString + jStr;
            }
        }
    }
    return maxL;