I appreciate everyone effort here but guy's the question here is to Not Use any More pointer (Rather Space Utilization).. I Donno , if there is a any way to detect without any further space.. Else my First Solution works neatly...
Br, On Thu, Dec 8, 2011 at 11:34 PM, himanshu kansal < [email protected]> wrote: > @sayan: take a singley linked list (not circular) with a loop in it....try > to reverse it.....you will get why i gave this algo...it can be > reversed....and it always ends up landing at original head of list if it > contains a loop.... > give it a try... > > > On Thu, Dec 8, 2011 at 11:30 PM, sayan nayak <[email protected]> wrote: > >> @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. >> > > > > -- > > 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.
