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potrue
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Sep 29, 2025
| fewest_num_coins[sub_amount] = [fewest_num_coins[sub_amount - coin] + 1, fewest_num_coins[sub_amount]].min | ||
| end | ||
| end | ||
| fewest_num_coins[amount] == Float::INFINITY ? not_existed : fewest_num_coins[amount] |
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not_existedは変数に置かないでいいと思います。置くとしてもこの行の前でいいと思いました。
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コメントありがとうございます！
定数におきたいのですがRubyはメソッドの中で定数を定義できないので変数にしています。
（メソッドの外には定義できるが、スコープが広くなるのでやりたくない）
一方で、おっしゃる通り場所は直前で良いかもしれませんね。
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Ruby っぽくないのかもしれませんが、
return -1 if fewest_num_coins[amount] == Float::INFINITY # not existed
fewest_num_coins[amount]くらいのほうが素直ではないでしょうか。
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確かにコメントで補足するという手もありですね。ありがとうございます。
potrue
reviewed
Sep 29, 2025
| fewest_num_coins[0] = 0 | ||
| 1.upto(amount).each do |sub_amount| | ||
| coins.each do |coin| | ||
| next if sub_amount - coin < 0 |
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どちらでもよいと思いますが、0から順にsub_amountを見ていってsub_amount + coin <= amountの場合にsub_amount + coinの場所を更新していく方法もあると思いました。
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解いた問題
322. Coin Change
使用言語
Ruby
次に解く問題
35. Search Insert Position