Question

我的C＃代码中的数学或组合数学有一个小问题。我不知道怎么写这个最简单。

我有一个Section和TestClass类，但是没有一个返回预期结果的方法。

public class Section
{
    public int Id { get; set; }
    public int Pages { get; set; }
    public string Name { get; set; }
}

[TestFixture]
public class PermutatorTest
{
    private IList<Section> _sections;
    private int _targetPage;

    [SetUp]
    public void SetUp()
    {
        _targetPage = 30;
        _sections = new List<Section>
        {
            new Section {Id = 1, Pages = 15, Name = "A"},
            new Section {Id = 2, Pages = 15, Name = "B"},
            new Section {Id = 3, Pages = 10, Name = "C" },
            new Section {Id = 4, Pages = 10, Name = "D"},
            new Section {Id = 5, Pages = 10, Name = "E"},
            new Section {Id = 6, Pages = 5, Name = "F"}
        };
    }

    [Test]
    public void GetPermutationsTest()
    {
        // Code to return list of all combinations
    }
}

我想获得每种组合，这些组合总共能给我30页。它可以根据名称或ID作为字符串返回，例如AA或11，AB或12 当然，顺序并不重要（AB和BA相同... CCD，CDC和DCC也是如此）

最终结果应如下所示：（30个正确结果）

AA
AB
ACF
ADF
AEF
AFFF
BB
BCF
BDF
BEF
BFFF
CCC
CCD
CCE
CDD
CEE
CDE
CFFFF
CDFF
CCFF
CEFF
DDFF
DEFF
DFFFF
DDD
DDE
EFFFF
EEE
EEFF
FFFFFF

例如DDE = 10 + 10 + 10 = 30 OK CFFFF = 10 + 5 +5 +5 +5 = 30好等

我不知道为此创建循环并将记录放入列表的最佳方法非常感谢您为我提供的一切帮助。

Answer 1

这是我要为您发布的最初想法，它只是返回了一个字符串列表

public List<String> result;
public void GetResultList(int startOffs, String CurNames, int curTotal)
{
  for (int newOffs = startOffs; newOffs < _sections.Count; newOffs++)
  {
    int newTotal = curTotal + _sections[newOffs].Pages;
    String newNames = CurNames+ _sections[newOffs].Name;
    if (newTotal < _targetPage)
      GetResultList(newOffs, newNames, newTotal);
    else if (newTotal == _targetPage)
      result.Add(newNames);
  }
}

通过初始化结果和开始参数来调用：

result = new List<String>();
GetResultList(0,"",0);

这是经过修改以使用您的Config类的版本

public void GetResultList(int startOffs, Config CurConfig)
{
  for (int newOffs = startOffs; newOffs < _sections.Count; newOffs++)
  {
    Config newConfig = new Config{ Name = CurConfig.Name + _sections[newOffs].Name,
                                   Ids = CurConfig.Ids + _sections[newOffs].Id.ToString(),
                                   Pages = CurConfig.Pages + _sections[newOffs].Pages};
    if (newConfig.Pages < _targetPage)
      GetResultList(newOffs, newConfig);
    else if (newConfig.Pages == _targetPage)
      _result.Add(newConfig);
  }
}

调用需要结果初始化和启动Config实例

_result = new List<Config>();
Config s = new Config { Ids = "", Pages=0, Name=""};
GetResultList(0,s);

Answer 2

仅适用于信息和搜索者。我知道，这段代码不是很干净但是我把它放在这里作为nUnit测试...

它返回我想要的...我想。

using System;
using System.Collections.Generic;
using NUnit.Framework;

[TestFixture]
public class PermutatorTest
{
    private IList<Section> _sections;
    private int _targetPage;
    private IList<Config> _result;
    [SetUp]
    public void SetUp()
    {
        _targetPage = 30;
        _sections = new List<Section>
        {
            new Section {Id = 1, Pages = 15, Name = "A"},
            new Section {Id = 2, Pages = 15, Name = "B"},
            new Section {Id = 3, Pages = 10, Name = "C" },
            new Section {Id = 4, Pages = 10, Name = "D"},
            new Section {Id = 5, Pages = 10, Name = "E"},
            new Section {Id = 6, Pages = 5, Name = "F"}
        };

        _result = new List<Config>();
    }

    [Test]
    public void GetPermutationsTest()
    {

        for (var b =0 ; b<=_sections.Count-1; b++)
        {
            var config = new Config
            {
                Name = _sections[b].Name,
                Ids =  _sections[b].Id.ToString(),
                Pages = _sections[b].Pages
            };
            GoDeeperAndAddToResult(config, b);
        }

        Console.WriteLine(_result.Count);

        foreach (var item in _result)
        {
            Console.WriteLine($"{item.Name} - {item.Ids} - {item.Pages}");
        }
    }

    private void GoDeeperAndAddToResult(Config config, int startIndex)
    {
        for (var b = startIndex; b <= _sections.Count-1; b++)
        {
            var section = _sections[b];

            var combName = config.Name;
            var combIds = config.Ids;
            var combPages = config.Pages;

            var maxSec = _targetPage / section.Pages;
            for (var a = 1; a <= maxSec; a++)
            {
                combName = combName + section.Name;
                combIds = combIds + section.Id.ToString();
                combPages = combPages + section.Pages;

                var subConfig = new Config
                {
                    Name = combName,
                    Ids = combIds,
                    Pages = combPages
                };

                if (subConfig.Pages == _targetPage)
                {
                    _result.Add(subConfig);
                    break;
                }
                else if (subConfig.Pages < _targetPage)
                {
                    GoDeeperAndAddToResult(subConfig, b + 1);
                }
                else
                {
                    break;
                }
            }
        }
    }

    public class Config
    {
        public string Name { get; set; }
        public string Ids { get; set; }
        public int Pages { get; set; }
    }

    public class Section
    {
        public int Id { get; set; }
        public int Pages { get; set; }
        public string Name { get; set; }
    }
}

有条件的循环。具体问题

2 个答案: