vb.net Getting numbers from array horizontally and vertically? - vb.net

Question

I have this crazy array.
ReDim arrayDeCeldas(filas - 1, columnas - 1)
For i = 0 To filas - 1
For j = 0 To columnas - 1
arrayDeCeldas(i, j) = i & j
Debug.Write(arrayDeCeldas(i, j) & " ")
Next j
Debug.WriteLine("")
Next i
And I'm trying to link it to a number of conditions and is not well to do
I'm trying to try to get 6 index from array
The number can't repeat and it are pick horizontally or vertically randomly
0 1 2 3 4 5 6 7
10 11 12 13 14 15 16 17
20 21 22 23 24 25 26 27
30 31 32 33 34 35 36 37
40 41 42 43 44 45 46 47
This example about i'm try.
It can be seen, there are a total of 6 items with different sizes
Actually my code, it's getting huge
Private Sub setBarco()
Dim numeroRandom As New System.Random()
Dim indiceA, indiceB As Integer
For b = 1 To barcos
Randomize()
Dim value As Integer = CInt(Int((2 * Rnd() + 1)))
indiceA = numeroRandom.Next(0, filas)
indiceB = numeroRandom.Next(0, columnas)
Select Case b
Case 1
If arrayDeCeldas(indiceA, indiceB) = 0 Then
arrayDeCeldas(indiceA, indiceB) = b & 1
End If
Case 2
Select Case value
Case 1
For c = 0 To 1
If indiceB + c < columnas Then
If arrayDeCeldas(indiceA, indiceB + c) = 0 Then
arrayDeCeldas(indiceA, indiceB + c) = b & c
End If
Else
If arrayDeCeldas(indiceA, indiceB - c) = 0 Then
arrayDeCeldas(indiceA, indiceB - c) = b & c
End If
End If
Next
Case 2
For c = 0 To 1
If indiceA + c < filas Then
If arrayDeCeldas(indiceA + c, indiceB) = 0 Then
arrayDeCeldas(indiceA + c, indiceB) = b & c
Else
End If
Else
End If
Next
End Select
Case 3
Case 4
Case 5
Case 6
End Select
Next b
End Sub

Answer 1

Based on your comment-reply, I understand the program must:
Pick at random any six elements from a 2D-array, and each element or value must be selected only once.
That's fairly straightforward: here's a pseudo-code implementation:
Perform some initial computation:
Get the bounds of the 2D array
Seed a random number generator:
Create a HashSet instance
Get six pairs of coordinates:
Loop continuously until HashSet has 6 elements in it:
Generate a coordinate pair within the bounds of the array found in Step 1.
Get the value from the coordinate pair
Check to see if we've seen the value before (by looking at the HashSet). If we've not seen it before, then add it to the HashSet and continue, otherwise ignore it and try again.
Return the contents of the HashSet
In C# this would be:
Int32[,] numbers = new Int32[] { ... };
Int32 maxY = numbers.GetUpperBound(0); // y-axis in dimension 0
Int32 maxX = numbers.GetUpperBound(1); // x-axis in dimension 1
Random rng = new Random();
HashSet<Int32> values = new HashSet<Int32>();
while( values.Count < 6 ) {
Int32 x = rng.Next( maxX + 1 ); // Random.Next is upperbound exclusive, hence +1
Int32 y = rng.Next( maxY + 1 );
Int32 value = numbers[ y, x ];
if( !values.Contains( value ) ) values.Add( value );
}
return values.ToArray();
Note that by keeping track of observed values, instead of coordinates, we can simultaneously avoid duplicate values and duplicate coordinates: as duplicate coordinates will give you duplicate values anyway.