public static int[] ColumnSum_PerColumn(this int[,] array2D)
{
int numColumns = array2D.NumColumns();
int[] columnSum_PerColumn = new int[numColumns];
for (int columnIndex = 0; columnIndex < numColumns; columnIndex++)
{
columnSum_PerColumn[columnIndex] = array2D.Column(columnIndex).Sum();
}
return(columnSum_PerColumn);
}
public void GetColumn()
{
int[,] x =
{
{ 11, 12, 13, 14, 15 },
{ 21, 22, 23, 24, 25 },
{ 31, 32, 33, 34, 35 },
{ 41, 42, 43, 44, 45 }
};
Assert.Equal(new[] { 12, 22, 32, 42 }, x.Column(1));
}
public static IEnumerable <(int, int)> Calculate(int[,] matrix)
{
for (var row = 0; row < matrix.RowCount(); row++)
{
for (var col = 0; col < matrix.ColumnCount(); col++)
{
if (IsSaddlePoint(row, col))
{
yield return(row + 1, col + 1);
}
}
}
bool IsSaddlePoint(int row, int col)
{
var value = matrix[row, col];
return(matrix.Row(row).All(n => n <= value) &&
matrix.Column(col).All(n => n >= value));
}
}