Dijkatra 迪克斯特拉双栈算术表达式求值算法 Java

import java.util.Stack;

/**
 * Created by yywang on 2017/1/14.
 */
public class Evaluate {

    static double evaluate(String tmp){
        Stack ops = new Stack();
        Stack vals = new Stack();
        for (int i=0; i//运算符压入 操作符栈
            if(s.equals("(")) ;
            else if(s.equals("+")) ops.push(s);
            else if(s.equals("-")) ops.push(s);
            else if(s.equals("*")) ops.push(s);
            else if(s.equals("/")) ops.push(s);
            else if(s.equals(")")){
                //遇到右括号开始计算
                String op = ops.pop();
                double v = vals.pop();
                if (op.equals("+")) v = vals.pop() + v;
                if (op.equals("-")) v = vals.pop() - v;
                if (op.equals("*")) v = vals.pop() * v;
                if (op.equals("/")) v = vals.pop() / v;

                vals.push(v);
            }else{
                //数字压入 操作数栈
                vals.push(Double.parseDouble(s));
            }

        }
        return vals.pop();
    }
    public static void main(String[] args) {
        String t = "(1+((2+3)*(4*5)))";
        double ret = evaluate(t);
        System.out.println(ret);
    }
}

输出结果

101.0