Create 1.scala

2018/Scala/1.scala

@@ -0,0 +1,31 @@
+import scala.collection.mutable
+import scala.io.Source
+import scala.collection.immutable.LazyList.#::
+
+val lines = Source.fromFile(getClass.getResource("/file.txt").getFile).getLines().toList
+
+// Solution 1
+val result1 = lines.foldLeft (0) { (acc, i) => acc + Integer.parseInt(i) }
+println(result1)
+
+// Solution 2
+val hash = new mutable.HashSet[Int]()
+
+def toLazyLoop[A](list: List[A]): LazyList[A] = {
+  def toLazy[A](list: List[A]): LazyList[A] = {
+    list match {
+      case List() => LazyList()
+      case h::t => h #:: toLazy(t)
+    }
+  }
+  toLazy(list) #::: toLazyLoop(list)
+}
+
+def findFirstRepeat[A](lazylist:LazyList[String], acc:Int, hash:mutable.HashSet[Int]):Int =
+  if (!hash.add(acc)) acc
+  else lazylist match {
+    case hd #:: tl => findFirstRepeat(tl, (acc + hd.toInt), hash)
+  }
+
+val result2 = findFirstRepeat(toLazyLoop(lines), 0, hash)
+println("First repeat frequency: " + result2)