Correct variable names consist only of English letters, digits and underscores and they can't start with a digit.

Check if the given string is a correct variable name.

Example

• For name = "var_1__Int", the output should be**solution(name) = true**;
• For name = "qq-q", the output should be**solution(name) = false**;
• For name = "2w2", the output should be**solution(name) = false**.

Input/Output

• [execution time limit] 3 seconds (java)

• [memory limit] 1 GB

• [input] string name

  Guaranteed constraints:

  1 ≤ name.length ≤ 10.

• [output] boolean

  true if name is a correct variable name, false otherwise.

풀이

boolean solution(String name) {
    // 첫 문자 숫자 확인용 정규화
    String REGEXP_PATTERN_NUMBER = "^[\\\\d]*$";
    // 문자만 허용;
    String REGEXP_PATTERN_CHAR = "^[\\\\w]*$";
    
    if (Pattern.matches(REGEXP_PATTERN_NUMBER, Character.toString(name.charAt(0)))) return false;
    if (Pattern.matches(REGEXP_PATTERN_CHAR, name)) return true;
    else return false;
}