obelisk2 https://blog.hatena.ne.jp/obelisk2/ Camera Obscura https://obelisk.hatenablog.com/ Swift 数学 こんな感じ。 eratosthenes.swift func eratosthenes(_ n: Int) -> [Int] { var ar = Array(0...n) for i in 2...Int(sqrt(Double(n))) { if ar[i] == 0 {continue} for j in 2...(n / i) {ar[i * j] = 0} } return ar.filter {$0 != 0} } print(eratosthenes(1000)) 1000万までの素数を求めてみました（出力はしていません）。Swift 4.0, Linux Mint 18.2。 … 190 <iframe src="https://hatenablog-parts.com/embed?url=https%3A%2F%2Fobelisk.hatenablog.com%2Fentry%2F2017%2F10%2F05%2F145618" title="Swift でエラトステネスの篩 - Camera Obscura" class="embed-card embed-blogcard" scrolling="no" frameborder="0" style="display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;"></iframe> Hatena Blog https://hatena.blog 2017-10-05 14:56:18 rich https://obelisk.hatenablog.com/entry/2017/10/05/145618 1.0 100%