how to create a table of 10 arbitrary ranges and pick appropriate intervals in java?

Question

here's a set of numbers between [0,100].How to create a table of 10 arbitrary ranges to store them and pick appropriate intervals? My idea is to first create an array and cut 0~100 randomly. I'm stuck here.... How to create the intervals in a sequential order but also randomly?

score 2 · Answer 1 · edited May 23 '17 at 12:20

2

Choose 9 distinct (without replacement) values between 0 and 100. Sort them (if you use the solution in the thread I linked, they'll already be sorted), and use them as your interval boundaries.

EDIT: If the ranges are allowed to be empty, don't even worry about uniqueness; just pick 9 random values, sort them, and you have your interval boundaries.

edited May 23 '17 at 12:20

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answered Feb 11 '14 at 20:08

TypeIA

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Thanks for your advice!!But what I mean is that I need the [0,100] to be cut into a sequential order such like [0,13],[14,45],[46,48]...some intervals like that.The boundaries I create must be in order. – user3298812 Feb 11 '14 at 20:27
@user3298812 Yes, my solution can give you that. Is there something I need to try to explain differently? – TypeIA Feb 11 '14 at 20:35
I saw that into more details and found the answer! Thanks a lot! You made my day ! – user3298812 Feb 11 '14 at 20:49

score 0 · Answer 2 · answered Feb 11 '14 at 21:46

Here is Java implementation for this task:

import java.util.*;

public class Intervals {
    public static int[][] getIntervals(int lowBound, int highBound,
            int intervalCount) {
        int intervalLength = highBound - lowBound;
        boolean[] used = new boolean[intervalLength + 1];
        used[0] = true;
        used[intervalLength] = true;
        Random r = new Random();
        for (int i = 0; i < intervalCount - 1; i++) {
            int candidate = 0;
            while (used[candidate]) {
                candidate = lowBound + r.nextInt(intervalLength);
            }
            used[candidate] = true;
        }
        int[][] result = new int[intervalCount][2];
        int previous = -1;
        int next;
        int count = 0;
        for (int i = 1; i <= intervalLength; i++) {
            if (used[i]) {
                next = i;
                result[count][0] = previous + 1 + lowBound;
                result[count][1] = next + lowBound;
                count++;
                previous = next;
            }
        }
        return result;
    }

    public static void main(String[] args) {
        System.out.println(Arrays.deepToString(getIntervals(0, 100, 10)));
    }

}

how to create a table of 10 arbitrary ranges and pick appropriate intervals in java?

2 Answers2