public void CodedTriangleNumbers()
{
string content = ScriptTools.Cat(@"C:\euler\p042_words.txt");
var words = content.Replace("\"", "").Split(new char[] { ',' });
var numbers = words.Map <string, int>(word => word.Map <char, int>(c => c - 'A' + 1).Sum());
var triangles = Itertools.Range(1, 1000).Map <int, int>(i => i * (i + 1) / 2);
var result = 0;
foreach (var number in numbers)
{
if (triangles.Contains(number))
{
result++;
}
}
Console.WriteLine("result is {0}", result);
}
public void TriangularPentagonalAndHexagonal()
{
var triangulars = Itertools.Range(1, (long)100000).Map <long, long>(n => n * (n + 1) / 2);
var pentagonals = Itertools.Range(1, (long)100000).Map <long, long>(n => n * (3 * n - 1) / 2);
var hexagonals = Itertools.Range(1, (long)100000).Map <long, long>(n => n * (2 * n - 1));
var zipped = triangulars
.Concat(pentagonals)
.Concat(hexagonals)
.Group()
.Filter(g => g.Length == 3);
foreach (var item in zipped)
{
Console.WriteLine("{0}", item[0]);
}
}
public void PrimePowerTriples()
{
// 7072
// 369
// 85
var squres = Itertools
.Range(2, 7072)
.Filter(x => x.IsPrime())
.Map <int, int>(x => x * x);
var cubes = Itertools
.Range(2, 369)
.Filter(x => x.IsPrime())
.Map <int, int>(x => x * x * x);
var fourth = Itertools
.Range(2, 85)
.Filter(x => x.IsPrime())
.Map <int, int>(x => x * x * x * x);
var numbers = new HashSet <int>();
foreach (var s in squres)
{
foreach (var c in cubes)
{
foreach (var f in fourth)
{
var p = s + c + f;
if (p > 50000000)
{
continue;
}
if (!numbers.Contains(p))
{
numbers.Add(p);
}
}
}
}
Console.WriteLine("{0}", numbers.Count());
}