具有上限和下限的Powerset(Powerset with upper and lower limits)

 我有一个过程，我需要找到符合特定标准的所有最佳组合。 Powersets是我认为我正在寻找的，但我想建立一些过滤器以避免数百万的结果。 
 
 例如，我有以下对象： 
 
public class CableReel
    {
        public string ReelId { get; set; }
        public int Length { get; set; }
    }
 
 我想获得上述目标的幂集，其中组合长度也满足下限和上限。 
 
 以下列表： 
 
 “a”，5200“b”，2500“c”，1000 
 
 我想加入以下限制，最小3000，最大5000.我想只看到BC组合。 
 
 我找到了以下用于返回通用powersets的代码： 
 
public IEnumerable<IEnumerable<T>> GetPowerSet<T>(List<T> list)
    {
        return from m in Enumerable.Range(0, 1 << list.Count)
               select
                 from i in Enumerable.Range(0, list.Count)
                 where (m & (1 << i)) != 0
                 select list[i];
    }
 
 我只是想知道如何调整它以完成我想要做的事情？ 
 
 解： 
 
 使用Alex Sikilinda的建议，我想出了： 
 
var ls = new List<CableReel>
            {
                new CableReel{Length = 5,ReelId = "A"},
                new CableReel{Length = 3,ReelId = "B"},
                new CableReel{Length = 2,ReelId = "C"},
                new CableReel{Length = 7,ReelId = "e"},
                new CableReel{Length = 3,ReelId = "f"},
                new CableReel{Length = 2,ReelId = "g"}

            };
    var p = GetPowerSet(ls).Where(psl => psl.Sum(ps => ps.Length) > 5 && psl.Sum(ps => ps.Length) < 8);

I have a process where I need to find all of the best combinations that fit a certain criteria. Powersets are what I think I am looking for, but i'd like to build in some filters in to avoid millions of results.
 
For example I have the following Object:
 
public class CableReel
    {
        public string ReelId { get; set; }
        public int Length { get; set; }
    }
 
I'd like to get a powerset of the above object where the combined lengths meet a lower limit and also an upper limit as well.
 
The following list:
 
"a", 5200 "b", 2500 "c", 1000
 
I'd like to put in the following limits, min 3000, max 5000. I'd like to then only see the BC combination. 
 
I have found the following code for returning generic powersets:
 
public IEnumerable<IEnumerable<T>> GetPowerSet<T>(List<T> list)
    {
        return from m in Enumerable.Range(0, 1 << list.Count)
               select
                 from i in Enumerable.Range(0, list.Count)
                 where (m & (1 << i)) != 0
                 select list[i];
    }
 
I was just wondering how this might be adapted to accomplish what I am looking to do? 
 
Solution:
 
Using Alex Sikilinda's advice I came up with:
 
var ls = new List<CableReel>
            {
                new CableReel{Length = 5,ReelId = "A"},
                new CableReel{Length = 3,ReelId = "B"},
                new CableReel{Length = 2,ReelId = "C"},
                new CableReel{Length = 7,ReelId = "e"},
                new CableReel{Length = 3,ReelId = "f"},
                new CableReel{Length = 2,ReelId = "g"}

            };
    var p = GetPowerSet(ls).Where(psl => psl.Sum(ps => ps.Length) > 5 && psl.Sum(ps => ps.Length) < 8);

原文：https://stackoverflow.com/questions/30464368