通用散列法,完美的散列Lecture 8: Universal Hashing, Perfect Hashing |
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课程网址: | http://videolectures.net/mit6046jf05_leiserson_lec08/ |
主讲教师: | Charles E. Leiserson |
开课单位: | 麻省理工学院 |
开课时间: | 2009-02-10 |
课程语种: | 英语 |
中文简介: | "哈希。今天我们要做一些惊人的东西与哈希。而且, 真的, 这是如此整洁的东西, 太不可思议了。我们将首先解决哈希的一个基本弱点。也就是说, 对于任何哈希函数的选择都存在一组错误的键, 所有的键都散列到同一个插槽中。还行。所以你选择一个哈希函数。我们研究了一些在实践中似乎效果很好的东西, 这些方法很容易输入到您的代码中。但无论你选哪一个, 总会有一些不好的钥匙。所以你可以想象, 只是把这一点赶回家一点...... "// |
课程简介: | //"Hashing. Today we're going to do some amazing stuff with hashing. And, really, this is such neat stuff, it's amazing. We're going to start by addressing a fundamental weakness of hashing. And that is that for any choice of hash function There exists a bad set of keys that all hash to the same slot. OK. So you pick a hash function. We looked at some that seem to work well in practice, that are easy to put into your code. But whichever one you pick, there's always some bad set of keys. So you can imagine, just to drive this point home a little bit..."// |
关 键 词: | 算法导论; 通用散列法; 点积 |
课程来源: | 视频讲座网 |
最后编审: | 2020-05-22:王淑红(课程编辑志愿者) |
阅读次数: | 115 |