MinStack.js

// description: https://leetcode-cn.com/explore/interview/card/top-interview-questions-easy/24/design/59/
// 最小栈

/**
 * initialize your data structure here.
 */
var MinStack = function() {
  this.stack = [];
};

/**
 * @param {number} x
 * @return {void}
 */
MinStack.prototype.push = function(x) {
  this.stack.push(x);
};

/**
 * @return {void}
 */
MinStack.prototype.pop = function() {
  this.stack.pop();
};

/**
 * @return {number}
 */
MinStack.prototype.top = function() {
  return this.stack[this.stack.length - 1];
};

/**
 * @return {number}
 */
MinStack.prototype.getMin = function() {
  return this.stack.reduce((ret, cur) => {
    return ret > cur ? cur : ret;
  }, Number.MAX_SAFE_INTEGER);
};

/**
 * Your MinStack object will be instantiated and called as such:
 * var obj = Object.create(MinStack).createNew()
 * obj.push(x)
 * obj.pop()
 * var param_3 = obj.top()
 * var param_4 = obj.getMin()
 */