Leetcode150. 逆波兰表达式求值

Grairain

于 2021-04-07 16:35:08 发布

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分类专栏： Leetcode刷题文章标签： leetcode

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class Solution {
public:
    int evalRPN(vector<string>& tokens) {
        stack<int> s;
        for(int i = 0; i < tokens.size(); i++){
            if(tokens[i] == "+" || tokens[i] == "-" || tokens[i] == "*" || tokens[i] == "/") {
                int num1 = s.top();
                s.pop();
                int num2 = s.top();
                s.pop();
                if (tokens[i] == "+") s.push(num2 + num1);
                if (tokens[i] == "-") s.push(num2 - num1);
                if (tokens[i] == "*") s.push(num2 * num1);
                if (tokens[i] == "/") s.push(num2 / num1);
            }else{
                s.push(stoi(tokens[i]));
            }
        }
        return s.top();
    }
};