Data commit

Task/Pi/Scala/pi.scala

@@ -0,0 +1,36 @@
+object Pi {
+  class PiIterator extends Iterable[BigInt] {
+    var r: BigInt = 0
+    var q, t, k: BigInt = 1
+    var n, l: BigInt = 3
+
+    def iterator: Iterator[BigInt] = new Iterator[BigInt] {
+      def hasNext = true
+
+      def next(): BigInt = {
+        while ((4 * q + r - t) >= (n * t)) {
+          val nr = (2 * q + r) * l
+          val nn = (q * (7 * k) + 2 + (r * l)) / (t * l)
+          q = q * k
+          t = t * l
+          l = l + 2
+          k = k + 1
+          n = nn
+          r = nr
+        }
+        val ret = n
+        val nr = 10 * (r - n * t)
+        n = ((10 * (3 * q + r)) / t) - (10 * n)
+        q = q * 10
+        r = nr
+        ret
+      }
+    }
+  }
+
+  def main(args: Array[String]): Unit = {
+    val it = new PiIterator
+    println("" + (it.head) + "." + (it.take(300).mkString))
+  }
+
+}