// Eric LippertのクイズをC#からJavaに移植
// http://b...content-available-to-author-only...n.com/b/ericlippert/archive/2012/02/24/a-simple-puzzle.aspx
// http://d...content-available-to-author-only...e.jp/matarillo/20120226/p1
 
import java.util.Random;
 
class Main {
    /**
     * 指定した範囲内の度数分布表を作成します。
     * bucketsには1以上の値が与えられるものとします。
     * maxにはminより大きな値が与えられるものとします。
     * @param data 度数分布表を作成するデータ。
     * @param buckets 作成する度数分布表の階級数（区間の数）。
     * @param min 作成する度数分布表の最小値。この値以上のデータを集計し、この値未満のデータは無視します。
     * @param max 作成する度数分布表の最大値。この値未満のデータを集計し、この値以上のデータは無視します。
     * @return 累積度数の配列。長さはbuckets。
     */
    private static int[] createHistogram(double[] data, int buckets, double min, double max) {
        // 累積度数の配列を作成。
        int[] results = new int[buckets];
        // 階級幅の逆数を計算。
        double multiplier = buckets / (max - min);
        for (double datum : data)
        {
            // 幅で割って（＝幅の逆数を掛けて）整数化。
            int index = (int)((datum - min) * multiplier);
            // 度数分布表の範囲に収まっていたら度数をカウントアップ。
            if (0 <= index && index < buckets)
                results[index] += 1;
        }
        return results;
    }
 
    public static void main(String[] args) {
        Random r = new Random();
        // 0以上100未満のランダムな数を100000個生成。
        double[] data = new double[100000];
        for (int i = 0; i < data.length; i++)
            data[i] = 100.0 * r.nextDouble();
        // 10以上20未満の区間を10個に分割した度数分布表を作成。
        int[] hist = createHistogram(data, 10, 10.0, 20.0);
        for (int i = 0; i < hist.length; i++)
            System.out.println(i + ": " + hist[i]);
    }
}

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