• Biased Random Number Generator


    I am looking for a random number generator that is biased towards giving numbers "furthest away" from a set of already selected numbers. 
    For example, if my range is [1, 50] and I pass in a set of numbers such as (1, 20, 40),
    then I would want the generator to "prefer" producing numbers further away from 1, 20, and 40.
    Therefore, numbers such as 50 or 30 would be more likely to be drawn than 20 or 40.
    I suspect that this may already exist. Does anyone know of such an implementation that I can use for Java?

    Here is a way you can do it by hand. Basically the idea is we take in some numbers we don't want to generate, then we generate a random number and if that number is in the list of numbers we don't want we try again up to a maximum number of retries.

    public static void main(String[] args) {
    
            int times = 25;
            int[] listOfNumbers = {1, 2, 3};
            int max = 5, min = 1;
    
            while(times-- > 0)
            {   
                System.out.print(GeneratePreferredNumbers(listOfNumbers, max, min) + " ");
            }
    
    
        }//main method
    
        public static Integer GeneratePreferredNumbers(int[] listOfNotPreffered, int max, int min)
        {
            Random rand = new Random();
            int randomNum;
            int retry = 1; //increasing this lessons the likely of our non-preferred numbers to show up
            HashSet<Integer> notPrefer = new HashSet<>();
    
            //add all the numbers we don't want to generate into a HashSet for easy lookup
            for(int index = 0; index < listOfNotPreffered.length; index++)
                notPrefer.add(listOfNotPreffered[index]);
    
            do {
                randomNum = rand.nextInt((max - min) + 1) + min;
                if(notPrefer.contains(randomNum))
                {
                    retry--;
                }
                //we found a good value, let's return it
                else{
                    retry = 0;
                }
            } while (retry > 0);
    
            return randomNum;
        }
    

      NOTE: The more times we allow the algorithm to retry the more likely our output will consist of numbers we want. This allows you to control how likely you want those non-preferred numbers to show up. This makes sense because if we were to increase the retry to infinite, this would stop only when the number generated is not contained in our list non-preferred numbers.

  • 相关阅读:
    2020牛客多校第三场 G
    Travel Guide
    jQuery属性选择器中加变量
    css 两大特性:继承性和层叠性
    css 伪元素选择器
    css 伪类选择器
    css属性选择器
    css的高级选择器,后代选择器,子代选择器,并集选择器,交集选择器
    css 引入方式以及css的选择器
    HTML
  • 原文地址:https://www.cnblogs.com/apanda009/p/7953008.html
Copyright © 2020-2023  润新知