solution1.6.2.2 added

Signed-off-by: Andreas Roehler <[email protected]>

chapter01/worksheets/solution1.6.2.2.scala

@@ -0,0 +1,19 @@
+/** author: Andreas Röhler */ 
+
+/** 
+  Exercise 1.6.2.2
+  An integer n is called a “3-factor” if it is divisible by only three different integers i,j,k
+such that 1 < i,j,k < n. Compute the set of all “3-factor” integers n among n ∈ [1, ..., 1000] .
+  */
+
+val p =  (1 to 1000)
+val q =  (2 to 999)
+
+val r =  p.map(x => q.filter(y => (x != y) && (x % y == 0)) )
+val s = p zip r
+val t = s.map{ case (x, y) => (x, y.length) } 
+val result = t.filter{ case (x, y) => 3 == y }.map{ case (x, y) => x }
+
+print("3-factor result among n ∈ [1, ..., 1000]: %s\n".format(result))
+
+// 3-factor result among n ∈ [1, ..., 1000]: Vector(16, 81, 625)