February 2017
Intermediate to advanced
368 pages
8h 21m
Japanese
Content preview from Optimized C++ ―最適化、高速化のためのプログラミングテクニック
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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.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.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.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.
204
9 章 探索と整列を最適化する
表
9-1
探索性能実験のまとめ
VS2010、i7、100 万回 前回からの改善％ カテゴリ改善％
map<string>
2,307
ミリ秒
map<char*>
自由関数
1,453
ミリ秒
59
％
59
％
map<char*>
関数オブジェクト
820
ミリ秒
77
％
181
％
map<char*>
ラムダ式
820
ミリ秒
0
％
181
％
std::find()
1,425
ミリ秒
std::equal
_
range()
1,806
ミリ秒
std::lower
_
bound
973
ミリ秒
53
％
86
％
find
_
binary
_
3way()
771
ミリ秒
26
％
134
％
std::unordered
_
map()
509
ミリ秒
find
_
hash()
195
ミリ秒
161
％
161
％
表
9-1
に探索実験の結果をまとめる。■
予想した通り、二分探索は線形探索より速く、ハッシュが二分探索より速かった。
C++
標準ライブラリは、多くの状況で役立つ多数のすぐに使えるデバッグ済みのアルゴリズム
とデータ構造とを用意している。標準は、最悪時コストを
O
表記で表し、広く使えるものだとい
うことを示している。しかし、標準ライブラリの非常に強力で汎用的な機構を使うにはコストがか
かる。良い性能の標準ライブラリアルゴリズムが存在する場合でも、専用に書いたアルゴリズムに
はかなわないことがよくある。これはテンプレートコードの弱点、あるいは、コンパイラ設計の弱
点、あるいは単に標準ライブラリコードが（
operator<() ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
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.