Sword finger offer 30 Stack containing min function

Original link ： The finger of the sword Offer 30. contain min Function of the stack

 

solution:
        Store with stack pair data , first Save the stacked elements ,second Save the minimum

class MinStack {
public:
    /** initialize your data structure here. */
    typedef pair<int,int> PII;
    stack<PII> stk;
    MinStack() {

    }
    
    //.first Save stack elements ,.second Save the minimum 
    void push(int x) {
        if(stk.empty() || x < stk.top().second) {
            stk.push({x, x});
            return;
        }
        stk.push({x, stk.top().second});
    }
    
    void pop() {
        stk.pop();
    }
    
    int top() {
        return stk.top().first;
    }
    
    int min() {
        return stk.top().second;
    }
};

/**
 * Your MinStack object will be instantiated and called as such:
 * MinStack* obj = new MinStack();
 * obj->push(x);
 * obj->pop();
 * int param_3 = obj->top();
 * int param_4 = obj->min();
 */