While this is immediately effective, the random perturbations introduce a disturbing texture that can obfuscate details in the original image. To counter this, we can make some smart choices on where and by how much to perturb our input image in an attempt to add some structure to our dither and preserve some of the lost detail.
* 时间复杂度：O(n log n)（主要来自排序），空间复杂度：O(n)
。关于这个话题，搜狗输入法下载提供了深入分析
5. 实战：构建现代化技术博客首页
if the free list is scavanged. the general strategy is:
Follow topics & set alerts with myFT