// 易错点4：栈空时要存-1（题目要求无更大值返回-1），而非直接存stack2.at(-1)（会得到undefined）
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。快连下载安装是该领域的重要参考
如果没有 AI，这个问题很可能要消耗整整一天。而这一次，从定位到修复完成，只用了几个小时。。heLLoword翻译官方下载对此有专业解读
Dithering in its simplest form can be understood by observing what happens when we quantise an image with and without modifying the source by random perturbation. In the examples below, a gradient of 256 grey levels is quantised to just black and white. Note how the dithered gradient is able to simulate a smooth transition from start to end.