C# 键值对列表
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Key Value Pair List
提问by user2778395
I have a list with below elements:
我有一个包含以下元素的列表：
{[A,1] ; [B,0] ; [C,0] ; [D,2]; [E,0] ; [F,8]}
When Variable =3 -> i want the return value to be A,D
当变量 =3 -> 我希望返回值为 A、D
When variable =11 -> return value to be A, D, F
当变量 =11 -> 返回值为 A, D, F
when 2 -> return value to be D
当 2 -> 返回值为 D
and so on.
等等。
int sum = myList.Sum(x => x.Value)
how to get the corresponding Key (A,D,F)?
如何获得对应的Key (A,D,F)？
回答by I4V
Using one of the subsetsmethod in this question
在这个问题中使用子集方法之一
var list = new List<KeyValuePair<string, int>>() {
new KeyValuePair<string, int>("A", 1),
new KeyValuePair<string, int>("B", 0),
new KeyValuePair<string, int>("C", 0),
new KeyValuePair<string, int>("D", 2),
new KeyValuePair<string, int>("E", 8),
};
int input = 11;
var items = SubSets(list).FirstOrDefault(x => x.Sum(y => y.Value)==input);
EDIT
编辑
a full console application:
一个完整的控制台应用程序：
using System;
using System.Collections.Generic;
using System.Linq;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
var list = new List<KeyValuePair<string, int>>() {
new KeyValuePair<string, int>("A", 1),
new KeyValuePair<string, int>("B", 2),
new KeyValuePair<string, int>("C", 3),
new KeyValuePair<string, int>("D", 4),
new KeyValuePair<string, int>("E", 5),
new KeyValuePair<string, int>("F", 6),
};
int input = 12;
var alternatives = list.SubSets().Where(x => x.Sum(y => y.Value) == input);
foreach (var res in alternatives)
{
Console.WriteLine(String.Join(",", res.Select(x => x.Key)));
}
Console.WriteLine("END");
Console.ReadLine();
}
}
public static class Extenions
{
public static IEnumerable<IEnumerable<T>> SubSets<T>(this IEnumerable<T> enumerable)
{
List<T> list = enumerable.ToList();
ulong upper = (ulong)1 << list.Count;
for (ulong i = 0; i < upper; i++)
{
List<T> l = new List<T>(list.Count);
for (int j = 0; j < sizeof(ulong) * 8; j++)
{
if (((ulong)1 << j) >= upper) break;
if (((i >> j) & 1) == 1)
{
l.Add(list[j]);
}
}
yield return l;
}
}
}
}
