p26 stub

Author: sandeepraju

src/main/scala/problems/p26/P26.scala

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+// references:
+// 1. http://aperiodic.net/phil/scala/s-99/p26.scala
+
+package problems.p26
+
+object P26 {
+
+  def main(args: Array[String]): Unit = {
+  }
+
+  def combinations[A](k: Int, ls: List[A]): List[List[A]] = ???
+}

src/main/scala/problems/p26/README.md

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+# P26. Generate the combinations of K distinct objects chosen from the N elements of a list.
+
+In how many ways can a committee of 3 be chosen from a group of 12 people? We all know that there are C(12,3) = 220 possibilities (C(N,K) denotes the well-known binomial coefficient). For pure mathematicians, this result may be great. But we want to really generate all the possibilities.
+
+## Example
+
+``` scala
+scala> combinations(3, List('a, 'b, 'c, 'd, 'e, 'f))
+res0: List[List[Symbol]] = List(List('a, 'b, 'c), List('a, 'b, 'd), List('a, 'b, 'e), ...
+```