2. 코드

package Test;

public class Pair {
    public static void main(String[] args) {
        String s = "((Hello))";
        Pair pair = new Pair();
        System.out.println(pair.check(s));
    }

    private boolean check(String s) {
        boolean result = true;
        int count = 0;

        for (int inx = 0; inx < s.length(); inx++) {
            char c = s.charAt(inx);

            if (c == '(')
                count++;
            else if (c == ')')
                count--;

            if (count < 0) {
                result = false;
                break;
            }
        }
        return result;
    }
}