[Algorithms] LeetCode 150. 逆波兰表达式求值

2025-04-22 13:39:21   2025-04-22 13:39:21
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来源：代码随想录

LeetCode 150. 逆波兰表达式求值

栈模拟

注意string的输入输出处理，小心负数。

class Solution {
public:
    int evalRPN(vector<string>& tokens) {
        stack<int> st;
        for (string s : tokens) {
            if (s == "+" || s == "-" || s == "*" || s == "/") {
                char c = s[0];
                int a = st.top();
                st.pop();
                int b = st.top();
                st.pop();
                if (c == '+') {
                    st.push(b + a);
                } else if (c == '-') {
                    st.push(b - a);
                } else if (c == '*') {
                    st.push(b * a);
                } else {
                    st.push(b / a);
                }
            } else {
                st.push(stoi(s));
            }
        }

        return st.top();
    }
};

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