Imports System
Module RandomOnesMatrix
'
' Generate N random 1s in a zero‑based matrix.
'
' Strategy:
' - Treat the matrix as a flat index space [0 .. rows*cols - 1].
' - Randomly pick unique positions using a Boolean helper array.
' - Convert each chosen flat index back to (row, col).
' - This avoids repeatedly searching for empty cells and keeps the logic simple.
'
' Print the matrix
Sub PrintMatrix(matrix As Integer(,), rows As Integer, cols As Integer)
For r = 0 To rows - 1
For c = 0 To cols - 1
Console.Write(matrix(r, c).ToString() & " ")
Next
Console.WriteLine()
Next
End Sub
' Allocate a rows×cols matrix initialized to zero
Function AllocateMatrix(rows As Integer, cols As Integer) As Integer(,)
Dim m(rows - 1, cols - 1) As Integer
' Elements are automatically initialized to zero
Return m
End Function
' Generate N random 1s in a zero-based matrix
Function GenerateRandomMatrix(rows As Integer, cols As Integer, count As Integer) As Integer(,)
Dim total As Integer = rows * cols
If count > total Then
Throw New ArgumentException("Requested more 1s than available cells.")
End If
' Allocate the matrix
Dim matrix As Integer(,) = AllocateMatrix(rows, cols)
' Temporary array to mark chosen positions
Dim chosen(total - 1) As Boolean
Dim rnd As New Random()
' Draw unique positions
Dim placed As Integer = 0
While placed < count
Dim index As Integer = rnd.Next(total)
If Not chosen(index) Then
chosen(index) = True
placed += 1
End If
End While
' Convert flat indices to (row, col)
For i = 0 To total - 1
If chosen(i) Then
Dim r As Integer = i \ cols
Dim c As Integer = i Mod cols
matrix(r, c) = 1
End If
Next
Return matrix
End Function
Sub Main()
Dim rows As Integer = 5
Dim cols As Integer = 7
Dim numberOfOnes As Integer = 10
Dim result As Integer(,) = GenerateRandomMatrix(rows, cols, numberOfOnes)
PrintMatrix(result, rows, cols)
End Sub
End Module
' run:
'
' 0 0 1 0 0 1 1
' 0 1 0 0 1 0 1
' 0 0 1 1 0 0 0
' 0 1 0 0 0 0 0
' 0 0 1 0 0 0 0
'
