Data commit

Task/Negative-base-numbers/Scala/negative-base-numbers-1.scala

@@ -0,0 +1,23 @@
+object NegativeBase {
+  val digits = ('0' to '9') ++ ('a' to 'z') ++ ('A' to 'Z')
+
+  def intToStr(n: Int, b: Int): String = {
+    def _fromInt(n: Int): List[Int] = {
+      if (n == 0) {
+        Nil
+      } else {
+        val r = n % b
+        val rp = if (r < 0) r + b else r
+        val m = -(n - rp)/b
+        rp :: _fromInt(m)
+      }
+    }
+    _fromInt(n).map(digits).reverse.mkString
+  }
+
+  def strToInt(s: String, b: Int): Int = {
+    s.map(digits.indexOf).foldRight((0, 1)){ case (x, (sum, pow)) =>
+      (sum + x * pow, pow * -b)
+    }._1
+  }
+}

Task/Negative-base-numbers/Scala/negative-base-numbers-2.scala

@@ -0,0 +1,9 @@
+def testConversion(b: Int)(n: Int, s: String): Unit = {
+  println(s"$n in base -$b = ${NegativeBase.intToStr(n, b)}")
+  println(s"$s from base -$b = ${NegativeBase.strToInt(s, b)}")
+}
+
+testConversion(2)(10, "11110")
+testConversion(3)(146, "21102")
+testConversion(10)(15, "195")
+testConversion(62)(795099356, "Scala")