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PONon-Uniform randomizer
 

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    <p>I need to to generate 6 unique random numbers from 1 to 37; At first I used a simple array mapping:</p> <pre><code>private int k=6, n=37; public int[] Results () { // fill an array with numbers 1 2 3 . . . n int[] numbers = new int[n]; for (int i = 0; i &lt; numbers.length; i++) numbers[i] = i + 1; // draw k numbers and put them into a second array int result[] = new int[k]; for (int i = 0; i &lt; result.length; i++) { // make a random index between 0 and n - 1 int r = (int) (Math.random() * n); // pick the element at the random location result[i] = numbers[r]; // move the last element into the random location numbers[r] = numbers[n - 1]; n--; } return result; } </code></pre> <p>The problem was that in a lot of the cases I got a near uniformic distribution (escpicially when I make less then 10 draws) i.e.: 1,9,16,18,24,30 or 5,16,18,22,26,29 </p> <p>What I really need is a TRUE randomizer that can give me results like: 11,16,25,29,30,32 or 4,8,9,15,18,19 in LESS then 10 draws.</p> <p>I saw also a HashMap implementation of something similar:</p> <pre><code>import java.util.*; public class RandomHash { HashMap numbers = new HashMap() ; Random rnd_gen = new Random() ; RandomHash() { for(;;) { int rnd_num = rnd_gen.nextInt() ; Integer rnd_num_obj = new Integer(rnd_num) ; if (! numbers.containsKey(rnd_num_obj) ) { numbers.put(rnd_num_obj, rnd_num_obj) ; /* Do whatever with the number */ break ; } /* else loop and get another rnadom num */ } /*end for*/ } } </code></pre> <p>The problem is that I currently don't know how to bound the randomizer and the hashmap to 6 and 32 respectively. Will the hashmap give more scrambled results ?</p>
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    1. CODefine "TRUE random" numbers, and show why the outputs you get were not TRULY random.
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    2. COWhat's "non-uniformic"? Do you mean "non-uniform"? What distribution do you require instead?
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