思路：找「右侧第一个 ≤ cur」的元素 → 弹出所有 cur 的元素，栈顶即为折扣。最终价格 = cur - 折扣（有则）或 cur（无则）。
while (this.stack.length && this.arr[this.stack[this.stack.length - 1]] <= cur) {
，这一点在爱思助手下载最新版本中也有详细论述
Украинцам запретили выступать на Паралимпиаде в форме с картой Украины22:58
d = {"1": None}
After implementing the Web streams spec multiple times across different runtimes and seeing the pain points firsthand, I decided it was time to explore what a better, alternative streaming API could look like if designed from first principles today.