Imports System
Imports System.Collections.Generic
Class Program
Private Shared Function ColumnsHaveUniqueNumbers(ByVal matrix As Integer(,)) As Boolean
Dim rows As Integer = matrix.GetLength(0)
Dim cols As Integer = matrix.GetLength(1)
For j As Integer = 0 To cols - 1
Dim columnSet As HashSet(Of Integer) = New HashSet(Of Integer)()
For i As Integer = 0 To rows - 1
If Not columnSet.Add(matrix(i, j)) Then
Return False
End If
Next
Next
Return True
End Function
Public Shared Sub Main()
Dim matrix1 As Integer(,) = {
{1, 4, 7},
{2, 5, 8},
{3, 6, 9}}
Dim matrix2 As Integer(,) = {
{1, 4, 7},
{2, 4, 8},
{3, 6, 9}}
Console.WriteLine("Matrix 1 columns have unique numbers: " & ColumnsHaveUniqueNumbers(matrix1))
Console.WriteLine("Matrix 2 columns have unique numbers: " & ColumnsHaveUniqueNumbers(matrix2))
End Sub
End Class
' run
'
' Matrix 1 columns have unique numbers: True
' Matrix 2 columns have unique numbers: False
'
