Evaluate Reverse Polish Notation

Evaluate the value of an arithmetic expression in Reverse Polish Notation.

Valid operators is + , - , * , / . Each operand is an integer or another expression.

Some Examples:

  ["2", "1", "+", "3", "*")--((2 + 1) (3)-9  ["4", "", "5", "/", "+"], 4 + (13/5))

classSolution { Public:    intEVALRPN (vector<string> &tokens) {Stack<int>Nums; intnum =tokens.size (); intI=0; if(num = =1)returnTonum (tokens[0]);  while(i<num) {             while(I<num &&!)Isop (Tokens[i])) {                intTMP =Tonum (Tokens[i]);                Nums.push (TMP); I++; }            intOP2 =Nums.top ();            Nums.pop (); intOP1 =Nums.top ();            Nums.pop (); if(Tokens[i] = ="+") {Nums.push (OP1+OP2); }            Else if(Tokens[i] = ="*") {Nums.push (OP1*OP2); }            Else if(Tokens[i] = ="-") {Nums.push (OP1-OP2); }            Else if(Tokens[i] = ="/") {Nums.push (OP1/OP2); } I++; }        returnNums.top (); }    intTonum (strings) {        intnum;        StringStream SS (s); SS>>num; returnnum; }    BOOLIsopstringstr) {        if(Str.length () >1)return false; if(str = ="+")return true; if(str = ="*")return true; if(str = ="-")return true; if(str = ="/")return true; }};

Evaluate Reverse Polish Notation