leetcode:逆波兰表达式求值

分析

典型stack

ac code

class Solution {
public:int evalRPN(vector<string>& tokens) {// 考虑stackstack<int> s;// for each for(auto token: tokens) {if(token &＃61;&＃61; "&＃43;" || token &＃61;&＃61; "-" || token &＃61;&＃61; "*" || token &＃61;&＃61; "/") {int b &＃61; s.top();s.pop();int a &＃61; s.top();s.pop();int c;// different operationsswitch(token.c_str()[0]) {case &＃39;&＃43;&＃39;: c &＃61; a &＃43; b;break;case &＃39;-&＃39;: c &＃61; a - b;break;case &＃39;*&＃39;: c &＃61; a * b;break;case &＃39;/&＃39;: c &＃61; a / b;break;}s.push(c);}else {s.push(stoi(token));}}return s.top();}
};


总结

cpp中的swtich要用char或int
string转char要c_str()