private static int GetRiskSum(string Input)
{
var matrix = ParseInput(Input);
var riskSum = 0;
foreach (var(x, y, value) in matrix.EveryPointIn())
{
var everyAdjacentIsLower = !(MatrixExtensions.IsInsideBounds(matrix, x + 1, y) && matrix[x + 1, y] <= value) &&
!(MatrixExtensions.IsInsideBounds(matrix, x, y + 1) && matrix[x, y + 1] <= value) &&
!(MatrixExtensions.IsInsideBounds(matrix, x - 1, y) && matrix[x - 1, y] <= value) &&
!(MatrixExtensions.IsInsideBounds(matrix, x, y - 1) && matrix[x, y - 1] <= value);
if (everyAdjacentIsLower)
{
riskSum += value + 1;
}
}
return(riskSum);
}
public void TestIsInsideBounds()
{
var matrix = new[, ] {
{ 0, 1 }
};
Assert.That(matrix[0, 1], Is.EqualTo(1));
var width = matrix.GetLength(0);
Assert.That(width, Is.EqualTo(1));
var height = matrix.GetLength(1);
Assert.That(height, Is.EqualTo(2));
Assert.That(MatrixExtensions.IsInsideBounds(matrix, 0, 1), Is.True);
Assert.That(MatrixExtensions.IsInsideBounds(matrix, -1, 0), Is.False);
Assert.That(MatrixExtensions.IsInsideBounds(matrix, 0, -1), Is.False);
Assert.That(MatrixExtensions.IsInsideBounds(matrix, 1, 0), Is.False);
Assert.That(MatrixExtensions.IsInsideBounds(matrix, 0, 2), Is.False);
}