If the sum of the subset is not equal to the specified value, the sum of the subset closest to the value

Question

I am working on the problem of the sum of a subset, which should print the sum of the subset closest to the value, if it is equal, then just type the value. Positive integers only

If there are several sums of a subset that are equally close to the value,

value = 10, subsetSum1 = 9, subsetSum2 = 11

print an amount less than the value.

Thus, the console application perfectly finds the equal amount of the subset, but how would I like to print the sum of the subset, which is closest to the value.

 class Program
    {
        static int[] elements;
        static int value;
        static bool solution = false;

        static void Main()
        {
            value = 10000;
            Console.WriteLine("How many numbers ?");
            int elementsQty = int.Parse(Console.ReadLine());
            elements = new int[elementsQty];
            for (int i = 0; i < elementsQty; i++)
            {
                elements[i] = int.Parse(Console.ReadLine());
            }
            Console.WriteLine("\nOutput:");
            List<int> subset = new List<int>();
            GetSubset(0, subset);
            if (!solution)
                Console.WriteLine("No match");

            Console.ReadLine();
        }

        static void GetSubset(int index, List<int> myElements)
        {
            if (myElements.Sum() == value && myElements.Count > 0) 
            {
                Console.WriteLine(" {0} = {1}", string.Join(" + ", myElements), value);
                solution = true; 
            }

            for (int i = index; i < elements.Length; i++)
            {
                myElements.Add(elements[i]);
                GetSubset(i + 1, myElements); 
                myElements.RemoveAt(myElements.Count - 1);
            }
        }
    }

Answer 1

. , . : (, 100+) .

, () , - .

, K, 2 K + 1 . null, 0, .

, :

7 -> _
6 -> _
5 -> _
4 -> _
3 -> _
2 -> _
1 -> _
0 -> []

if b=8 ( b=8 , , , ).

_ ( null) [] ( , ).

. ( null) . "" : , . , . :

for(int s = b-xi-1; s >= 0; s--) {
    if(cols[s+xi] == null && cols[s] != null) {
        List<int> cln = new List<int>(cols[s]);
        cln.Add(xi);
        cols[s+xi] = cln;
    }
}

xi , . , if , s ( null), : . for : : s+xi s . , s 0 () b-xi-1 ( ). , xi .

, , 2, () 0 8-2-1=5. , s=0, "" , :

7 -> _
6 -> _
5 -> _
4 -> _
3 -> _
2 -> [2]
1 -> _
0 -> []

([2] 2), for, s=1 , , , s=2 ​​. , , 2 , :

7 -> _
6 -> _
5 -> _
4 -> [2,2]
3 -> _
2 -> [2]
1 -> _
0 -> []

: , , , , . xi , , "" . , :

7 -> _
6 -> _
5 -> _
4 -> _
3 -> _
2 -> [2]
1 -> _
0 -> []

1, :

7 -> _
6 -> _
5 -> _
4 -> _
3 -> [2,1]
2 -> [2]
1 -> [1]
0 -> []

, 3, :

7 -> _
6 -> [2,1,3]
5 -> [2,3]
4 -> [1,3]
3 -> [2,1]
2 -> [2]
1 -> [1]
0 -> []

, 3 [3], . . , [2,1], [3], , .

, , null, . . , , , , K.

:

static List<int> GetSubset(int value, IEnumerable<int> xs) {
    int b = 2*value;
    List<int>[] cols = new List<int>[b];
    cols[0] = new List<int>();
    foreach(int xi in xs) {
        for(int s = b-xi-1; s >= 0; s--) {
            if(cols[s+xi] == null && cols[s] != null) {
                List<int> cln = new List<int>(cols[s]);
                cln.Add(xi);
                cols[s+xi] = cln;
            }
        }
    }
    for(int d = 0; d < value; d++) {
        if(cols[value-d] != null) {
            return cols[value-d];
        } else if(cols[value+d] != null) {
            return cols[value+d];
        }
    }
    return cols[0];
}

List<T> : (, , .NET, , ).

( csharp):

$ csharp
Mono C# Shell, type "help;" for help

Enter statements below.
csharp> public class Foo {
      >  
      > public static List<int> GetSubset(int value, IEnumerable<int> xs) {
      >         int b = 2*value;
      >         List<int>[] cols = new List<int>[b];
      >         cols[0] = new List<int>();
      >         foreach(int xi in xs) {
      >             for(int s = b-xi-1; s >= 0; s--) {
      >                 if(cols[s+xi] == null && cols[s] != null) {
      >                     List<int> cln = new List<int>(cols[s]);
      >                     cln.Add(xi);
      >                     cols[s+xi] = cln;
      >                 }
      >             }
      >         }
      >         for(int d = 0; d < value; d++) {
      >             if(cols[value-d] != null) {
      >                 return cols[value-d];
      >             } else if(cols[value+d] != null) {
      >                 return cols[value+d];
      >             }
      >         }
      >         return cols[0];
      >     }
      > }
csharp>  
csharp> int[] items = new int[] {2,3,5,7};
csharp> Foo.GetSubset(8,items);
{ 3, 5 }
csharp> Foo.GetSubset(7,items); 
{ 2, 5 }
csharp> Foo.GetSubset(9,items); 
{ 2, 7 }
csharp> Foo.GetSubset(6,items); 
{ 2, 3 }
csharp> Foo.GetSubset(10,items); 
{ 2, 3, 5 }
csharp> Foo.GetSubset(11,items); 
{ 2, 3, 5 }

, 6 , , 5.

, : , , K, K + 1, K-1 .. , .