CycleNode.java

//Where you detect the LinkedList Cycle return that Node

/**
 * Definition for singly-linked list.
 * class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }
 */
public class Solution {
    public ListNode detectCycle(ListNode head) {
        int length=0;
        ListNode fast=head;
        ListNode slow=head;

        while(fast!=null && fast.next!=null)
        {
            fast=fast.next.next;
            slow=slow.next;
            if(fast==slow)
            {
                length=lengthCou(head);
                break;
            }
        }

        if(length==0)
        {
            return null;
        }

        ListNode f=head;
        ListNode s=head;

        while(length>0)
        {
            f=f.next;
            length--;
        }

        while(f!=s)
        {
            f=f.next;
            s=s.next;
        }
        return f;
    }

    private int lengthCou(ListNode head)
    {
        int length=0;
        ListNode fast=head;
        ListNode slow=head;

        while(fast!=null && slow!=null)
        {
            fast=fast.next.next;
            slow=slow.next;
            if(fast==slow)
            {
                ListNode temp=slow;
                do{
                    temp=temp.next;
                    length+=1;
                }while(temp!=slow);
                return length;
            }
        }
        return 0;
    }
}