UVA - 673-Parentheses Balance

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




public class Main {

    public static void main(String[] args) throws IOException{
       InputStreamReader isr=new InputStreamReader(System.in);
       BufferedReader br=new BufferedReader(isr);
       int cases= Integer.parseInt(br.readLine());
       StringBuilder out = new StringBuilder("");
       for(int i=0;i<cases;i++){
           String str=br.readLine();
           if("".equals(str)){
               out.append("Yes").append("\n");
               continue;
           }
           Stack<Character> stack=new Stack<Character>();
           if(str.charAt(0)==']' ||str.charAt(0)==')'){
               out.append("No").append("\n");
               continue;
           }
           stack.push(str.charAt(0));
           for(int j=1;j<str.length();j++){
               char temp=str.charAt(j);
               if(temp=='[' || temp=='('){
                   stack.push(str.charAt(j));
               }
               if(temp==']'){
                   if(stack.isEmpty()){
                       stack.push(temp);
                       break;
                   }
                  if(stack.peek()=='[')
                     stack.pop();
                  else{
                      stack.push(temp);
                      break;
                  }
               }
               if(temp==')'){
                   if(stack.isEmpty()){
                       stack.push(temp);
                       break;
                   }
                  if(stack.peek()=='(')
                     stack.pop();
                  else{
                      stack.push(temp);
                      break;
                  }
               }
           }
           if(stack.isEmpty())
                out.append("Yes");
           else
               out.append("No");
           out.append("\n");
       }
       System.out.print(out);
    }
}