Regular expression to check if the consecutive chars exist.

regular_expression_consecutive_chars.java

// 문자열에 연속되는 문자가 있는지 확인
public static boolean checkConsecutiveChars(@NonNull String password, int consecutiveLength) {

    if (password.length() < consecutiveLength) {
        return false;
    }

    for (int i = 0; i <= password.length() - consecutiveLength; i++) {
        char s1 = password.charAt(i);
        char s2 = password.charAt(i + 1);
        char s3 = password.charAt(i + 2);
        if (Math.abs(s1 - s2) == 1 && s1 - s2 == s2 - s3) {
            return true;
        }
    }

    return false;

}