/** A histogram of floating-point values */
public interface Histogram {
    /** The number of buckets in THIS. */
    int size();

    /** Lower bound of bucket #K. Pre: 0<=K<size(). */
    double low(int k);

    /** # of values in bucket #K. Pre: 0<=K<size(). */
    int count(int k);

    /** Add VAL to the histogram. */
    void add(double val);
}