Data commit

Task/EKG-sequence-convergence/Kotlin/ekg-sequence-convergence.kotlin

@@ -0,0 +1,49 @@
+// Version 1.2.60
+
+fun gcd(a: Int, b: Int): Int {
+    var aa = a
+    var bb = b
+    while (aa != bb) {
+        if (aa > bb)
+            aa -= bb
+        else
+            bb -= aa
+    }
+    return aa
+}
+
+const val LIMIT = 100
+
+fun main(args: Array<String>) {
+    val starts = listOf(2, 5, 7, 9, 10)
+    val ekg = Array(5) { IntArray(LIMIT) }
+
+    for ((s, start) in starts.withIndex()) {
+        ekg[s][0] = 1
+        ekg[s][1] = start
+        for (n in 2 until LIMIT) {
+            var i = 2
+            while (true) {
+                // a potential sequence member cannot already have been used
+                // and must have a factor in common with previous member
+                if (!ekg[s].slice(0 until n).contains(i) &&
+                    gcd(ekg[s][n - 1], i) > 1) {
+                        ekg[s][n] = i
+                        break
+                }
+                i++
+            }
+        }
+        System.out.printf("EKG(%2d): %s\n", start, ekg[s].slice(0 until 30))
+    }
+
+    // now compare EKG5 and EKG7 for convergence
+    for (i in 2 until LIMIT) {
+        if (ekg[1][i] == ekg[2][i] &&
+        ekg[1].slice(0 until i).sorted() == ekg[2].slice(0 until i).sorted()) {
+            println("\nEKG(5) and EKG(7) converge at term ${i + 1}")
+            return
+        }
+    }
+    println("\nEKG5(5) and EKG(7) do not converge within $LIMIT terms")
+}