Initial data commit

Task/Yellowstone-sequence/Java/yellowstone-sequence.java

@@ -0,0 +1,54 @@
+import java.util.ArrayList;
+import java.util.List;
+
+public class YellowstoneSequence {
+
+    public static void main(String[] args) {
+         System.out.printf("First 30 values in the yellowstone sequence:%n%s%n", yellowstoneSequence(30));
+    }
+
+    private static List<Integer> yellowstoneSequence(int sequenceCount) {
+        List<Integer> yellowstoneList = new ArrayList<Integer>();
+        yellowstoneList.add(1);
+        yellowstoneList.add(2);
+        yellowstoneList.add(3);
+        int num = 4;
+        List<Integer> notYellowstoneList = new ArrayList<Integer>();
+        int yellowSize = 3;
+        while ( yellowSize < sequenceCount ) {
+            int found = -1;
+            for ( int index = 0 ; index < notYellowstoneList.size() ; index++ ) {
+                int test = notYellowstoneList.get(index);
+                if ( gcd(yellowstoneList.get(yellowSize-2), test) > 1 && gcd(yellowstoneList.get(yellowSize-1), test) == 1 ) {
+                    found = index;
+                    break;
+                }
+            }
+            if ( found >= 0 ) {
+                yellowstoneList.add(notYellowstoneList.remove(found));
+                yellowSize++;
+            }
+            else {
+                while ( true ) {
+                    if ( gcd(yellowstoneList.get(yellowSize-2), num) > 1 && gcd(yellowstoneList.get(yellowSize-1), num) == 1 ) {
+                        yellowstoneList.add(num);
+                        yellowSize++;
+                        num++;
+                        break;
+                    }
+                    notYellowstoneList.add(num);
+                    num++;
+                }
+            }
+        }
+        return yellowstoneList;
+    }
+
+    private static final int gcd(int a, int b) {
+        if ( b == 0 ) {
+            return a;
+        }
+        return gcd(b, a%b);
+    }
+
+}