Merge pull request #89 from robkeim/grains

Add Grains solution

config.json

@@ -12,6 +12,7 @@
     "rna-transcription",
     "sum-of-multiples",
     "space-age",
+    "grains",
     "hamming",
     "raindrops",
     "nucleotide-count",
@@ -131,6 +132,13 @@
         "Filtering"
       ]
     },
+    {
+      "slug": "grains",
+      "difficulty": 2,
+      "topics": [
+        "Integers"
+      ]
+    },
     {
       "slug": "raindrops",
       "difficulty": 2,
@@ -307,7 +315,7 @@
     {
       "slug": "allergies",
       "difficulty": 4,
-      "topics": [  	
+      "topics": [
         "Bitwise operations",
         "Filtering"
       ]

exercises/grains/Example.cs

@@ -0,0 +1,21 @@
+public class Grains
+{
+    public static ulong Square(int n)
+    {
+        return n == 1
+            ? 1
+            : 2 * Square(n - 1);
+    }
+
+    public static ulong Total()
+    {
+        ulong total = 0;
+
+        for (int i = 1; i <= 64; i++)
+        {
+            total += Square(i);
+        }
+
+        return total;
+    }
+}

exercises/grains/GrainsTest.cs

@@ -0,0 +1,60 @@
+using NUnit.Framework;
+
+[TestFixture]
+public class GrainsTest
+{
+    [Test]
+    public void Test_square_1()
+    {
+        Assert.That(Grains.Square(1), Is.EqualTo(1));
+    }
+
+    [Ignore("Remove to run test")]
+    [Test]
+    public void Test_square_2()
+    {
+        Assert.That(Grains.Square(2), Is.EqualTo(2));
+    }
+
+    [Ignore("Remove to run test")]
+    [Test]
+    public void Test_square_3()
+    {
+        Assert.That(Grains.Square(3), Is.EqualTo(4));
+    }
+
+    [Ignore("Remove to run test")]
+    [Test]
+    public void Test_square_4()
+    {
+        Assert.That(Grains.Square(4), Is.EqualTo(8));
+    }
+
+    [Ignore("Remove to run test")]
+    [Test]
+    public void Test_square_16()
+    {
+        Assert.That(Grains.Square(16), Is.EqualTo(32768));
+    }
+
+    [Ignore("Remove to run test")]
+    [Test]
+    public void Test_square_32()
+    {
+        Assert.That(Grains.Square(32), Is.EqualTo(2147483648));
+    }
+
+    [Ignore("Remove to run test")]
+    [Test]
+    public void Test_square_64()
+    {
+        Assert.That(Grains.Square(64), Is.EqualTo(9223372036854775808));
+    }
+
+    [Ignore("Remove to run test")]
+    [Test]
+    public void Test_total_grains()
+    {
+        Assert.That(Grains.Total(), Is.EqualTo(18446744073709551615));
+    }
+}