@Himanshu: How can u reverse a linked list which has only the beginning(head) but no tail...
And even if I consider that by some means u have reversed it..then also there is no guarantee that u reach the head.. Because the LinkedList is not necessarily circular..a circular Linkedlist and a linkedlist with loop are not same...Cicular is one specific case of Loop. Pls correct me If I have misunderstood your explanation. Regards, Sayan On Thu, Dec 8, 2011 at 10:27 PM, himanshu kansal < [email protected]> wrote: > if u cant create new ptrs....then i think horse and tortoise strategy will > fail..... > then you can only modify the linked lists to detect the loop..... > > one other strategy could be to reverse the linked list.....after reversing > the linked list, if you arrive at the head itself then the list contains > the loop.... > > i know reversing of list will require additional three ptrs....bt this is > also one of the way.... > > > On Thu, Dec 8, 2011 at 9:43 PM, hary rathor <[email protected]>wrote: > >> take two pointer >> run first with one speed and another with two until they meet, >> now take a first pointer and assign with head of list . >> now move again both same speed (only one forward at a time ) >> now as they meet at point that will be your starting pointer of loop. >> >> On 12/8/11, Deepak Nettem <[email protected]> wrote: >> > If you allow storing an extra bit with every node (to mark whether a >> node >> > has been visited), you can do it with just one pointer. But that's less >> > space efficient (O(n)) than using two pointers of varying speeds. >> > >> > On Thu, Dec 8, 2011 at 9:04 AM, Ankur Garg <[email protected]> >> wrote: >> > >> >> U cant create any new ptrs .Just use this ptr :) >> >> >> >> >> >> On Thu, Dec 8, 2011 at 6:30 PM, Prem Krishna Chettri >> >> <[email protected]>wrote: >> >> >> >>> Ofcourse we can.. >> >>> >> >>> U knw the head address now U start visit the list what is the big >> >>> deal?? Jst u gotto create two pointer say fast and slow with two diff >> >>> speed >> >>> of action.. >> >>> >> >>> On Thu, Dec 8, 2011 at 6:27 PM, Ankur Garg <[email protected]> >> wrote: >> >>> >> >>>> Can we detect if a loop is present in Linked List if only head ptr >> is >> >>>> given >> >>>> >> >>>> -- >> >>>> You received this message because you are subscribed to the Google >> >>>> Groups "Algorithm Geeks" group. >> >>>> To post to this group, send email to [email protected]. >> >>>> To unsubscribe from this group, send email to >> >>>> [email protected]. >> >>>> For more options, visit this group at >> >>>> http://groups.google.com/group/algogeeks?hl=en. >> >>>> >> >>> >> >>> -- >> >>> You received this message because you are subscribed to the Google >> Groups >> >>> "Algorithm Geeks" group. >> >>> To post to this group, send email to [email protected]. >> >>> To unsubscribe from this group, send email to >> >>> [email protected]. >> >>> For more options, visit this group at >> >>> http://groups.google.com/group/algogeeks?hl=en. >> >>> >> >> >> >> -- >> >> You received this message because you are subscribed to the Google >> Groups >> >> "Algorithm Geeks" group. >> >> To post to this group, send email to [email protected]. >> >> To unsubscribe from this group, send email to >> >> [email protected]. >> >> For more options, visit this group at >> >> http://groups.google.com/group/algogeeks?hl=en. >> >> >> > >> > >> > >> > -- >> > >> > -- >> > You received this message because you are subscribed to the Google >> Groups >> > "Algorithm Geeks" group. >> > To post to this group, send email to [email protected]. >> > To unsubscribe from this group, send email to >> > [email protected]. >> > For more options, visit this group at >> > http://groups.google.com/group/algogeeks?hl=en. >> > >> > >> >> >> -- >> Harish Pranami >> Master Of Computer Application , >> Deptt of computer Science, >> north campus , university of delhi, >> New Delhi pin no - 110007 >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Algorithm Geeks" group. >> To post to this group, send email to [email protected]. >> To unsubscribe from this group, send email to >> [email protected]. >> For more options, visit this group at >> http://groups.google.com/group/algogeeks?hl=en. >> >> > > > -- > > Regards > Himanshu Kansal > Msc Comp. sc. > (University of Delhi) > > > -- > You received this message because you are subscribed to the Google Groups > "Algorithm Geeks" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/algogeeks?hl=en. > -- You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/algogeeks?hl=en.
