afl-material: progs/pow.scala@8aa406adfde0 (annotated)

365 9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	1	def concat(A: Set[String], B: Set[String]) : Set[String] =
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	2	for (x <-A ; y <- B) yield x ++ y
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	3
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	4	def pow(A: Set[String], n: Int) : Set[String] = n match {
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	5	case 0 => Set("")
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	6	case n => concat(A, pow(A, n- 1))
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	7	}
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	8
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	9	val A = Set("a", "b", "c", "d")
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	10	pow(A, 4).size // -> 256
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	11
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	12	val B = Set("a", "b", "c", "")
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	13	pow(B, 4).size // -> 121
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	14
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	15	val C = Set("a", "b", "")
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	16	pow(C, 2)
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	17	pow(C, 2).size // -> 7
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	18
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	19	pow(C, 3)
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	20	pow(C, 3).size // -> 15

author	Christian Urban <christian dot urban at kcl dot ac dot uk>
	Thu, 26 Nov 2015 12:55:59 +0000
changeset 387	8aa406adfde0
parent 365	9b71dead1219
child 397	cf3ca219c727
permissions	-rw-r--r--