December 2016
Intermediate to advanced
440 pages
9h 44m
Japanese
Content preview from アルゴリズムクイックリファレンス 第2版
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378
■
11
章 新たな分類のアルゴリズム
11.4.2
探索木のサイズを推定する
数学者は長らく、チェス盤に
8
つのクイーンを置いて、どのクイーンも相手を取
れない位置にできるかを問う
8
クイーン問題を研究してきた。この問題を一般化し
て、
n
×
n
の盤上で
n
個のクイーンを互いに取り合わないような配置がいくつあるか
考えよう。数学的にこの答えを求める方法を示した人はまだいない。あらゆる可能
な配置を調べて答えを決定する力任せのプログラムを書くことはできる。表11-6に
は、オンライン整数列大事典（
On-Line Encyclopedia of Integer Sequences
）から
とった計算値が示されている（
https:
//
oeis.org
/
A000170
）。明らかに、解の個数
は急速に増える。
表11-6 nクイーン問題の解の既知の個数と計算した推定個数
n 実際の解の個数
T＝ 1,024 試行の
推定
T＝ 8,192 試行の
推定
T＝ 65,536 試行の
推定
1 1 1 1 1
2 0 0 0 0
3 0 0 0 0
4 2 2 2 2
5 10 10 10 10
6 4 5 4 4
7 40 41 39 40
8 92 88 87 93
9 352 357 338 351
10 724 729 694 718
11 2,680 2,473 2,499 2,600
12 14,200 12,606 14,656 13,905
13 73,712 68,580 62,140 71,678
14 365,596 266 ...
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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.