<p>Given a circular linked list, implement an algorithm that returns the node at the beginning of the loop.</p> <p>Circular linked list: A (corrupt) linked list in which a node's next pointer points to an earlier node, so as to make a loop in the linked list.</p> <p><strong>Example 1: </strong></p> <pre> <strong>Input: </strong>head = [3,2,0,-4], pos = 1 <strong>Output: </strong>tail connects to node index 1</pre> <p><strong>Example 2: </strong></p> <pre> <strong>Input: </strong>head = [1,2], pos = 0 <strong>Output: </strong>tail connects to node index 0</pre> <p><strong>Example 3: </strong></p> <pre> <strong>Input: </strong>head = [1], pos = -1 <strong>Output: </strong>no cycle</pre> <p><strong>Follow Up: </strong><br /> Can you solve it without using additional space?</p>