C＃随机算法直到满足条件 [英] C# Random algorithm until fulfills condition

问题描述

我有以下情况：

1. 生成 n 个随机数一定范围内


2. 所有数字求和


3. 检查 sum == x （x是用户设置的数字）


4. 如果 sum！= x 然后继续运行循环


5. 如果 sum == x ，则显示总计为 x 的随机数列表li>
   

1. Generate n numbers of random number from a certain range
2. Sum all the numbers
3. Check if the sum == x (x is a number set by user)
4. if sum != x then keep running the loop
5. If sum == x, then display the list of random numbers that sum up to x

基于此逻辑，我能够做到这一点，但是要永远达到结果，是否有更好的方法来解决这个问题

Based on this logic, I was able to do so but it takes forever to achieve the result, is there any better / way to solve this problem?

    static void Main(string[] args)
    {
        Console.WriteLine("starting...");
        List<int> checkList = generate(5);
        while(!checkSum(checkList, 100))
        {
            checkList = generate(5)
        }
        Console.WriteLine("done!");
    }


    private static bool checkSum(List<int> n, int sum)
    {
        if(n.Sum() == sum)
        {
            return true;
        }
        else
        {
            return false;
        }
    }


    public static List<int> generate(int n)
    {
        Random rng = new Random();
        List<int> list = new List<int>();
        for (int i = 0; i < 5; i++)
        {
            //int ran = some random number
            list.Add(ran);
        }

        return list;
    }

编辑

在这里，我的情况是获取总计为100的随机整数的 n 个组合。组合的数量取自用户的输入。因此，程序将给出 n 个可能的组合的总数，总计为100。

My scenario here is to obtain n combinations of random integer that sums up to 100. The number of combinations is taken from input by user. So the program will give the n number of possible combinations that sums up to 100.

可能的组合：

• 25 + 37 + 9 + 20 + 9 = 100


• 46 + 21 + 13 + 8 + 12 = 100

推荐答案

如果您有固定的总和和固定数量的元素， ，将问题视为分区。例如：

If you have a fixed sum and a fixed number of elements you want, look at the problem as partitioning. For example:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace PartitionAndAllocateTEst
{
    class Program
    {
        static void Main(string[] args)
        {
            var rand = new Random();
            int desiredTotal = 100;
            int partitions = 5;

            for (int i = 0; i < 10; i++)
            {
                List<int> result = GetRandomCollection(rand, desiredTotal, partitions);
                Console.WriteLine(string.Join(", ", result.Select(r => r.ToString()).ToArray()));
            }
        }

        private static List<int> GetRandomCollection(Random rand, int desiredTotal, int partitions)
        {
            // calculate the weights
            var weights = new List<double>();
            for (int i = 0; i < partitions; i++)
            {
                weights.Add(rand.NextDouble());
            }
            var totalWeight = weights.Sum();

            // allocate the integer total by weight
            // http://softwareengineering.stackexchange.com/questions/340393/allocating-an-integer-sum-proportionally-to-a-set-of-reals/340394#340394
            var result = new List<int>();
            double allocatedWeight = 0;
            int allocatedCount = 0;
            foreach (var weight in weights)
            {
                var newAllocatedWeight = allocatedWeight + weight;
                var newAllocatedCount = (int)(desiredTotal * (newAllocatedWeight / totalWeight));
                var thisAllocatedCount = newAllocatedCount - allocatedCount;
                allocatedCount = newAllocatedCount;
                allocatedWeight = newAllocatedWeight;

                result.Add(thisAllocatedCount);
            }

            return result;
        }
    }
}

示例输出：

30, 6, 19, 15, 30
36, 8, 22, 10, 24
2, 25, 32, 21, 20
22, 7, 30, 12, 29
36, 21, 22, 0, 21
24, 24, 2, 29, 21
18, 13, 10, 39, 20
11, 19, 20, 27, 23
24, 19, 7, 25, 25
24, 14, 27, 18, 17

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