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Check if a List Has a Loop

This function checks if a singly linked list has a loop in it.

It uses the same ListNode and List classes from the previous examples, but implements a new member method, HasLoop(). A list has a loop if there is some ListNode node in it for which node.next is equal to head.

Source Code

						1.     class List {
 2.
						3.         private ListNode head;
 4.
						5.         public List() {
 6.             head = null;
 7.         }
 8.
						9.         public List(ListNode ln) {
10.             head = ln;
11.         }
12.
						13.         public boolean HasLoop() {
14.
						15.             //
16.             // The algorithm is to start two pointers
17.             // at the head of the list; as the first pointer
18. // advances one element in the list, the second ...