백준 균형잡힌 세상

import java.util.*;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        Queue <Character> q = new LinkedList<>();
        ArrayList <Character> al = new ArrayList<>();

        while (true) {
            q.clear();
            al.clear();
            String str = sc.nextLine();
            if(str.equals(".")) {
                break;
            }
            String fis = "";

            for (int i = 0; i < str.length(); i++) {
                char t = str.charAt(i);
                if ((t == '(') || (t == ')') || (t == '[') || (t == ']')) {
                    q.add(t);
                    al.add(t);
                }
            }

            System.out.println(solver(q));
        }
    }

    private static String solver(Queue <Character> q) {

        Stack<Character> stack = new Stack<>();
        int n = q.size();
        for(int i=0 ; i<n ; i++ ) {
            char c = q.remove();
            if(c == '(' || c=='[') {
                stack.push(c);
            }
            else if(c == ')') {
                if(stack.empty() || stack.peek() != '(') {
                    return "no";
                }
                else {
                    stack.pop();
                }
            }
            else if( c==']') {
                // 스택이 비어있거나 pop할 원소가 대괄호랑 매칭이 안되는 경우
                if(stack.empty() || stack.peek() != '[') {
                    return "no";
                }
                else {
                    stack.pop();
                }
            }
        }
        if(stack.empty()) {
            return "yes";
        }
        else {
            return "no";
        }
        //return "";
    }

}