Dijkstra algorithm

// Dijkastra algorithm two-stack
value: push onto the value stack
operator: push onto the operator stack
left parenthesis: ignore
right parenthesis: pop operator and two values; push the result of applying that operator to those values onto the operand stack
public class Evaluate {
	public static void main (String [] args) {
		Stack<String> ops = new Stack <String> ();
		Stack<Double> vals = nerw Stack <Double>();
		while (!StdIn. isEmpty()){
			String s = StdIn.readString ();
			if (s.equals(Ò(Ò)) ;
			else if (s.equals(Ò+Ó)) 
				ops.push (s);
			else if (s.equals(Ò*Ó)) 
				ops.push (s);
			else if (s.equals(Ò)Ó)) {
				String op = ops.pop();
				if (op.equals(Ò+Ó))
					vals.push(vals.pop() + vals.pop ());
				else if (op.equals(Ò*Ó)) 
					vals.push(vals.pop() * vals.pop());
			}
			else vals.push(Double.parseDouble(s));
		}
		StdOut.println(vals.pop));
	}
}