包含min函数的栈

class Solution {
public:
    stack<int> data, minStack;
    void push(int value) {
        data.push(value);
        if(!minStack.empty()) {
            if(value < minStack.top()) 
                minStack.push(value);
        }
        else
            minStack.push(value);
        
    }
    void pop() {
        int val = data.top();
        data.pop();
        if(val == minStack.top()) 
            minStack.pop();
    }
    int top() {
        return data.top();
    }
    int min() {
        return minStack.top();
    }
};