August 2017
Intermediate to advanced
360 pages
8h 35m
Chinese
Content preview from 算法技术手册（原书第2 版）
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322
第
12
章
尾声：算法原理
不知不觉已经步入了本书的尾声，但这并不意味着关于算法方面的知识介绍已经到了尽
头。更确切地说，本书所介绍的这些技术所面向的问题是无穷无尽的。
本书详细讲解并提供示例的算法达
30
多个，现在我们终于有机会回顾一番了。我们希
望读者能够从始至终地赞同书中的讲解。为了展现本书所涉及内容的广度，我们将总结
书中所有算法背后的原理，以此来展示不同算法之间的相似性。我们不打算通过简单地
汇总各个章节来作为结束，而是将目光放在关键性原理上，这些原理正是最初设计这些
算法的动机。我们还将借此机会总结每种算法所涉及的概念，这样做不仅对这些算法进
行快速汇总，还有助于根据所共享的不同算法来设置索引。
12.1 了解数据
本书提及许多作用于数据之上的通用行为。例如，你也许需要通过对数据进行排序来产
生某个特定的顺序，或者需要搜索数据来寻找某些特殊的信息。数据可能是可以随机访
问的（也就是说，可以在任何时候读取任何一块数据），也有可能只能通过迭代器进行
顺序访问（每次只能处理一个元素）。如果不了解数据的特性，就只能使用一些较为通
用的算法。
通常，输入数据的特性对算法有着至关重要的影响。在第
9
章中，如果知道要计算的线
段交集不包含竖线，就可以很容易地过滤掉许多特例情况。类似地，如果没有任何两点
共享相同的
x
坐标或
y
坐标，就可以简化
Voronoi
图。再如第
6
章中的
Dijkstra
算法
，
如果存在一个边权和为负数的环，那么算法将会陷入死循环。在选择算法前，了解它们
的一些特例和前提假设是有必要的。
正如之前讨论过的，没有哪种算法 ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.