/**
* initialize your data structure here.
*/
var MinStack = function () {
// 声明一个辅助栈 用来存放 minValue
this.stack = [];
this.minStack = [Infinity];
};
/**
* @param {number} val
* @return {void}
*/
MinStack.prototype.push = function (val) {
// 入栈 同时 minStack 每次保留的都是最新的最小元素
this.stack.push(val);
this.minStack.push(Math.min(val, this.minStack[this.minStack.length - 1]));
};
/**
* @return {void}
*/
MinStack.prototype.pop = function () {
this.stack.pop();
this.minStack.pop();
};
/**
* @return {number}
*/
MinStack.prototype.top = function () {
return this.stack[this.stack.length - 1];
};
/**
* @return {number}
*/
MinStack.prototype.getMin = function () {
return this.minStack[this.minStack.length - 1];
};
/**
* Your MinStack object will be instantiated and called as such:
* var obj = new MinStack()
* obj.push(val)
* obj.pop()
* var param_3 = obj.top()
* var param_4 = obj.getMin()
*/