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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空间树结构
｜
295
空间树结构
•
所有叶结点位于同一层。
R
树是一个平衡结构，它能够确保上述列出的所有性质。为了方便起见，我们认为叶结
点所在的层次是第
0
层，而根结点的层次就是树的高度。
R
树结构能够在
O
(log
m
n
)
的时
间完成插入、删除和查询操作。
代码库中包含的示例应用可以用于调研
R
树的行为。图
10-17
所示为在包含
4
个形状（
M
=
4
）的
R
树中新加入
6
号矩形的动态行为。正如你所看到的，没有足够的空间能够容
纳新的矩形，因此相关的叶结点
R
1
被切分成两个
结点，并确保新的非叶结点
R
2
的面积
最小。新加入的矩形使
R
树的高度增加了
1
，因为它创建了新的根结点
R
3
。
S
2
S
2
S
4
S
3
图 10-17：R 树插入示例
R 树小结
最坏情况和平均情况：
O
(
log
m
n
)
最坏情况：
O
(
n
)
add (R, rect)
if R is empty then
R = new RTree (rect)
else
leaf = chooseLeaf(rect)
if leaf.count < M then
❶
add rect to leaf
else
newLeaf = leaf.split(rect)
❷
newNode = adjustTree (leaf, newLeaf)
❸
if newNode != null then
R = new RTree with old Root and newNode as children ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
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.