leetcode_27_最小栈

class MinStack {
public:MinStack() {}void push(int val) {//只要是压栈，先将元素保存到_elem中_elem.push(val);//如果x小于_min中栈顶的元素，将x再压入_min中if(_min.empty() || val <= _min.top()){_min.push(val);}}void pop() {//如果——min栈顶的元素 == 出栈的元素，_min顶的元素要移除if(_min.top() == _elem.top()){_min.pop();}_elem.pop();}int top() {return _elem.top();}int getMin() {return _min.top();}
private://保存栈中的元素std::stack<int> _elem;//保存栈的最小值std::stack<int> _min;
};/*** Your MinStack object will be instantiated and called as such:* MinStack* obj = new MinStack();* obj->push(val);* obj->pop();* int param_3 = obj->top();* int param_4 = obj->getMin();*/

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