leetcode_Evaluate Reverse Polish Notation

来源：互联网发布：东莞天迅网络编辑：程序博客网时间：2024/06/08 18:12

    /*     * Evaluate Reverse Polish Notation     * */    public int evalRPN(String[] tokens)     {    int result = 0;    Stack<Integer> mStack = new Stack<>();    for(String mString:tokens)    {    //mind the sequence of op1 and op2    if(mString.equals("+"))    {    Integer op1 = mStack.pop();    Integer op2 = mStack.pop();    Integer op3 = op2+op1;    mStack.push(op3);    }    else if(mString.equals("-"))    {    Integer op1 = mStack.pop();    Integer op2 = mStack.pop();    Integer op3 = op2-op1;    mStack.push(op3);    }    else if(mString.equals("*"))    {    Integer op1 = mStack.pop();    Integer op2 = mStack.pop();    Integer op3 = op2*op1;    mStack.push(op3);    }    else if(mString.equals("/"))    {    Integer op1 = mStack.pop();    Integer op2 = mStack.pop();    Integer op3 = op2/op1;    mStack.push(op3);    }    else     {    mStack.push(Integer.parseInt(mString));}    }    return mStack.pop().intValue();    }

总结延伸：逆波兰式计算、一些容器的使用

0 0