Added linked list with loop code

Author: gkcs

Diff for: .idea/compiler.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <module org.jetbrains.idea.maven.project.MavenProjectsManager.isMavenModule="true" type="JAVA_MODULE" version="4">
-  <component name="NewModuleRootManager" LANGUAGE_LEVEL="JDK_1_8" inherit-compiler-output="false">
+  <component name="NewModuleRootManager" LANGUAGE_LEVEL="JDK_1_8">
     <output url="file://$MODULE_DIR$/target/classes" />
     <output-test url="file://$MODULE_DIR$/target/test-classes" />
     <content url="file://$MODULE_DIR$">

Diff for: Competitive Programming.iml

@@ -0,0 +1,77 @@
+package main.java.videos;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Code to detect the start of a loop in a linked list.
+ * Requested by: Jayadev Senapathi Kota (Hi there!)
+ *
+ * Run this after removing the package statement above, and specifying the list.
+ *
+ * Sample Test Case:
+ *
+ * 1->2->3->4->5->6->3
+ *
+ * Output:
+ *
+ * We should have a loop at 3
+ * We have a loop! Meeting point is: 5
+ * The start of the loop is at 3!
+ */
+
+public class LinkedListWithLoop {
+    public static void main(String[] args) throws IOException {
+        final BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
+        final String nodes[] = bufferedReader.readLine().split("->");
+        final Node start = new Node(Integer.parseInt(nodes[0]));
+        Node current = start;
+        final Map<Integer, Node> values = new HashMap<>();
+        for (int i = 1; i < nodes.length; i++) {
+            final int value = Integer.parseInt(nodes[i]);
+            if (values.containsKey(value)) {
+                current.next = values.get(value);
+                System.out.println("We should have a loop at " + value);
+                break;
+            } else {
+                current.next = new Node(value);
+                values.put(value, current.next);
+                current = current.next;
+            }
+        }
+
+        Node hare = start, tortoise = start;
+        try {
+            do {
+                tortoise = tortoise.next;
+                hare = hare.next.next;
+            }
+            while (hare != tortoise);
+            System.out.println("We have a loop! Meeting point is: " + hare.value);
+            hare = start;
+            do {
+                tortoise = tortoise.next;
+                hare = hare.next;
+            }
+            while (hare != tortoise);
+            System.out.println("The start of the loop is at " + hare.value + "!");
+        } catch (NullPointerException loopNotDetected) {
+            System.out.println("I don't see a loop there!");
+        }
+    }
+
+
+    private static class Node {
+        Node next;
+        final int value;
+
+        public Node(final int value) {
+            this.value = value;
+        }
+    }
+}
+
+