[스택/큐] 올바른 괄호 (JAVA)

https://school.programmers.co.kr/learn/courses/30/lessons/12909

프로그래머스

import java.io.IOException;
import java.util.Stack;

class Solution {
    boolean solution(String s) throws IOException {
        boolean answer = true;
        Stack<Character> st = new Stack<>();
        char[] arr = s.toCharArray();

        for(int i = 0 ; i < s.length(); i++){
            if(st.isEmpty()){
                if(arr[i] == ')'){
                    return false;
                }
                st.push(arr[i]);
                continue;
            }
            if(arr[i] == '('){
                st.push(arr[i]); continue;
            }
            else{ // arr[i] == ')'
                if(st.peek() == '(') st.pop();
                else return false;
            }

        }

        if(st.isEmpty()) answer = true;
        else answer = false;

        return answer;
    }
}