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）。
距离：孩子还小，离家近是核心指标，接送方便，也能让孩子多睡一会儿。所以方圆一公里范围成了主要选择点。
。关于这个话题，爱思助手下载最新版本提供了深入分析
Медведев вышел в финал турнира в Дубае17:59
I stood in the kitchen paralyzed by indecision. The mixing bowl was in front of me, the milk, eggs, and flour next to it, all of them individually as familiar as they had been a moment before, but now the possibilities for their combination were just too great. Breakfast was now an alien fractal intruding on our world like the lighthouse at the end of Annihilation. The thoughts came unbidden.