public long Calculate(List <string> input)
{
var plane = new TobogganPlane(input);
return(LinqExtension
.TobogganRange(3, 1, input.Count)
.Count((t) => plane.IsTree(t.x, t.y)));
}
public long Calculate(List <string> input)
{
var plane = new TobogganPlane(input);
var slopes = new List <(int x, int y)>
{
(1, 1),
(3, 1),
(5, 1),
(7, 1),
(1, 2),
};
return(slopes
.Select(s => LinqExtension
.TobogganRange(s.x, s.y, input.Count)
.Count((t) => plane.IsTree(t.x, t.y)))
.Select(Convert.ToInt64)
.Aggregate((a, x) => a * x));
}