Add Floyd_Cycle_Loop_Detection in Java

Author: makajeez

Floyd Cycle Loop Detection/Floyd_Cycle_Loop_Detection.java

@@ -0,0 +1,59 @@
+// A linked list node
+class Node
+{
+	int data;
+	Node next;
+
+	Node(int data, Node next) {
+		this.data = data;
+		this.next = next;
+	}
+};
+
+class Main
+{
+	// Function to detect Cycle in a linked list using Hashing
+	public static boolean detectCycle(Node head)
+	{
+		Node curr = head;
+		Set<Node> set = new HashSet();
+
+		// traverse the list
+		while (curr != null)
+		{
+			// return false if we already have seen this node before
+			if (set.contains(curr)) {
+				return true;
+			}
+
+			// insert current node into the set
+			set.add(curr);
+
+			// move to the next node
+			curr = curr.next;
+		}
+
+		// we reach here if list does not contain any cycle
+		return false;
+	}
+
+	// Detect Cycle in a linked list
+	public static void main(String[] args)
+	{
+		// input keys
+		int[] keys = {1, 2, 3, 4, 5};
+
+		Node head = null;
+		for (int i = keys.length - 1; i >= 0; i--)
+			head = new Node(keys[i], head);
+
+		// insert cycle
+		head.next.next.next.next.next = head.next.next;
+
+		if (detectCycle(head)) {
+			System.out.println("Cycle Found");
+		} else {
+			System.out.println("No Cycle Found");
+		}
+	}
+}