public class Stack<T> extends MyArrayList<T>
{
    public T peek()
    {
      if(size==0) return null; //throw new NoSuchElementException("whatever");
      return A[size-1];
    }

    public T pop()
    {
      T tmp=peek();
      size--;
      return tmp;
    }

    public void push(T item)
    {
      add(item);
    }

    //1-based index from the top of stack
    //if o is not in stack, return -1
    public int search(Object o)
    {
      if(size==0) return -1;

      for(int i=size-1;i>=0;i--)
      {
        if(A[i]==o)
        {
          return size-i;
        }
      }

      return -1;
    }

    public void print()
    {
      System.out.print("[");
      for(int i=0;i<size;i++)
        System.out.print(A[i]+" ");
      System.out.println("]");
    }

    public static void main(String [] args)
    {

      String [] X={"(([{<>}])<[{}]>)",
                   "((())",
                   "",
                   "[(])",
                   "{(<[{<{<>{}>}}]){}}",
                   "{(<>[{<>}]){}}"
                 };

      for(int j=0;j<X.length;j++)
      {
        String Y=X[j];
        boolean balanced=true;
        Stack<Character> S=new Stack<>();
        
        for(int i=0;i<Y.length();i++)
        {
            char c=Y.charAt(i);
            if(c=='<' || c=='(' || c=='[' || c=='{' )
              S.push(c);
            else if(c=='>')
            {
              if(S.peek()=='<') S.pop();
              else{ balanced=false; break; }
            }
            else if(c==')')
            {
              if(S.peek()=='(') S.pop();
              else{ balanced=false; break; }
            }
            else if(c=='}')
            {
              if(S.peek()=='{') S.pop();
              else{ balanced=false; break; }
            }
            else if(c==']')
            {
              if(S.peek()=='[') S.pop();
              else{ balanced=false; break; }
            }
        }//end of for i

        if(S.size()!=0) balanced=false;

        if(balanced)
          System.out.println(Y+" is balanced size="+S.size());
        else
          System.out.println(Y+" is NOT balanced size="+S.size());
      }//end of for j

      // S.push("abc");
      // S.push("gmu");
      // S.push("is");
      // S.push("the");
      // S.push("best");
      // S.pop();
      // S.push("bestest");
      // S.print();
    }

}