栈（stack）是先进后出的数据结构。单调栈在入栈时通过一定规则保持栈内元素有序（单调递增或单调递减），从而把「找左侧/右侧第一个更大/更小元素」从 O(n²) 降到 O(n)。
Copied to clipboard。关于这个话题，新收录的资料提供了深入分析
"Quite literally, I did not have a microphone, but I had a karaoke game on the Nintendo Wii and they gave you a mic with the game. And I just was like, 'It has a USB connection, maybe it will work plugged it in'.。新收录的资料对此有专业解读
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