afl-material: progs/pow.scala@7a04f2c532c1 (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
397 cf3ca219c727 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: 365 diff changeset	15	val B2 = Set("a", "b", "c", "")
cf3ca219c727 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: 365 diff changeset	16	pow(B2, 3).size // -> 40
cf3ca219c727 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: 365 diff changeset	17
365 9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	18	val C = Set("a", "b", "")
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	19	pow(C, 2)
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	20	pow(C, 2).size // -> 7
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	21
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	22	pow(C, 3)
9b71dead1219 updated Christian Urban <christian dot urban at kcl dot ac dot uk> parents: diff changeset	23	pow(C, 3).size // -> 15

author	Christian Urban <christian dot urban at kcl dot ac dot uk>
	Tue, 20 Sep 2016 12:17:01 +0100
changeset 421	7a04f2c532c1
parent 397	cf3ca219c727
child 471	9476086849ad
permissions	-rw-r--r--