gomi-box https://blog.hatena.ne.jp/gomi-box/ 毛のはえたようなもの https://gomi-box.hatenablog.com/ Ruby ProjectEuler n × (n - 1) × ... × 3 × 2 × 1 を n! と表す。100! の各桁の数字の合計を求めよ。 Problem 20 - PukiWiki def make_array(num) array = [] while num > 0 num,tmp = num.divmod(10) array.unshift(tmp) end return array end sum = 1 (2..100).each{|n| sum = sum * n} ans =0 make_array(sum).each{|i| ans += i} p ans 答え：648 190 <iframe src="https://hatenablog-parts.com/embed?url=https%3A%2F%2Fgomi-box.hatenablog.com%2Fentry%2F20081026%2FPE_P20" title="Problem 20 - 毛のはえたようなもの" 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 2008-10-26 00:00:00 rich https://gomi-box.hatenablog.com/entry/20081026/PE_P20 1.0 100%