actually for each number you are finding how many sequences can be formed ending at that particular number which have sum less than the value.
so the algorithm is like --- we need to find how many sums are less than candidate Sum chosen in one iteration of binary search in range 0-S. To count this, for each i we try to find how many sums ending at i are lesser than candidate sum !! On Wed, Feb 22, 2012 at 10:41 AM, atul anand <atul.87fri...@gmail.com>wrote: > /* > algo goes as follows > *do a binary search in range 0-S*, for each such candidate sum find how > many sums are smaller than candidate sum > */ > do a binary search in range 0-S--> to search what?? > acc to the complexity , O(N *log S) it seems that you are searching each > element in given input array from range 0-S > for given input = 1,2,3,4,5 > S= 15 > > please clarify ..... sorry but i am not getting it ... > > > > > > > On Wed, Feb 22, 2012 at 10:25 AM, sunny agrawal > <sunny816.i...@gmail.com>wrote: > >> Yes, read my first post >> >> >> On Wed, Feb 22, 2012 at 10:19 AM, atul anand <atul.87fri...@gmail.com>wrote: >> >>> sum[0-1] = 3 --> (1,2) >>> sum[0-2] = 6 --> (1,2,3) >>> sum[1-2] = 5 --> (2,3) >>> >>> ok...so we can consider 3 , (1,2) as different contiguous. >>> >>> how did you choose candidate sum for the given input ?? will it not add >>> to the complexity >>> >>> >>> On Wed, Feb 22, 2012 at 9:59 AM, sunny agrawal >>> <sunny816.i...@gmail.com>wrote: >>> >>>> @atul there are 8 sums less than 7 >>>> >>>> sum[0 - 0] = 1 >>>> sum[1-1] = 2 >>>> sum[2 - 2] = 3 >>>> sum[3-3] = 4 >>>> sum[4-4] = 5 >>>> sum[0-1] = 3 >>>> sum[0-2] = 6 >>>> sum[1-2] = 5 >>>> >>>> contiguous sum (1,2) , (2,3) --> these contiguous sum has already been >>>> counted ??? where ? >>>> Read problem statement carefully !! >>>> >>>> >>>> On Wed, Feb 22, 2012 at 9:39 AM, atul anand <atul.87fri...@gmail.com>wrote: >>>> >>>>> @sunny : before moving to your algorithm , i can see wrong output in >>>>> your example:- >>>>> >>>>> in you example dere are 8 sums less than 7. >>>>> but for given input contiguous sum less than 7 are >>>>> 1,2,3,4,5 = 4 >>>>> so output is 4. >>>>> >>>>> correct me if i am wrong... >>>>> >>>>> >>>>> On Wed, Feb 22, 2012 at 12:41 AM, sunny agrawal < >>>>> sunny816.i...@gmail.com> wrote: >>>>> >>>>>> we need to find how many sums are less than candidate Sum chosen in >>>>>> one iteration of binary search in range 0-S >>>>>> To count this, for each i we try to find how many sums ending at i >>>>>> are lesser than candidate sum !! >>>>>> >>>>>> lets say for some i-1 sum[0 - i-1] < candidate sum then we can say >>>>>> that i*(i-1)/2 sums are less than candidate sum. >>>>>> now lets say after adding a[i] again sum[0 - i] < candidateSum then u >>>>>> can add (i+1) to previous count because all sums [0 - i], sum[1 - i], >>>>>> ............. sum[i - i] will be lesser than candidate sum >>>>>> or if adding a[i] causes sum[0 - i] > candidateSum then u have to >>>>>> find a index g such that sum[g - i] < candidate sum, and increase the >>>>>> count >>>>>> by ((i)-(g) +1). >>>>>> >>>>>> eg lets say your candidate sum is 7 (for the given >>>>>> example{1,2,3,4,5}) k = 3 n = 5 >>>>>> initially g = 0 >>>>>> sum = 0; >>>>>> candidateSum = 7; >>>>>> count = 0 >>>>>> iteration one: >>>>>> sum[0 - 0] = 1 < 7 so count += 0-0+1; >>>>>> >>>>>> iteration 2 >>>>>> sum[0-1] = 3 < 7, count += 1-0+1 >>>>>> >>>>>> iteration 3 >>>>>> sum[0-2] = 6 < 7 count += 2-0+1; >>>>>> >>>>>> iteration 4 >>>>>> sum[0,3] = 10 > 7 so now increment g such that sum[g,i] < 7 >>>>>> so g = 3 count += 3-3+1; >>>>>> >>>>>> iteration 5 >>>>>> sum[3 - 4] = 9 > 7 >>>>>> new g = 4 count += 4-4+1 >>>>>> >>>>>> final count = 8, so there are 8 sums less than 7 >>>>>> >>>>>> >>>>>> >>>>>> On Wed, Feb 22, 2012 at 12:16 AM, shady <sinv...@gmail.com> wrote: >>>>>> >>>>>>> didn't get you, how to check for subsequences which doesn't start >>>>>>> from the beginning ? can you explain for that same example... should we >>>>>>> check for all contiguous subsequences of some particular length? >>>>>>> >>>>>>> >>>>>>> On Tue, Feb 21, 2012 at 11:15 PM, sunny agrawal < >>>>>>> sunny816.i...@gmail.com> wrote: >>>>>>> >>>>>>>> i dont know if a better solution exists >>>>>>>> but here is one with complexity O(N*logS)... >>>>>>>> N = no of elements in array >>>>>>>> S = max sum of a subarray that is sum of all the elements as all >>>>>>>> are positive >>>>>>>> >>>>>>>> algo goes as follows >>>>>>>> do a binary search in range 0-S, for each such candidate sum find >>>>>>>> how many sums are smaller than candidate sum >>>>>>>> >>>>>>>> there is also need to take care of some cases when there are >>>>>>>> exactly k-1 sums less than candidate sum, but there is no contigious >>>>>>>> where >>>>>>>> sum = candidate sum. >>>>>>>> >>>>>>>> >>>>>>>> On Tue, Feb 21, 2012 at 11:02 PM, shady <sinv...@gmail.com> wrote: >>>>>>>> >>>>>>>>> Problem link <http://www.spoj.pl/ABACUS12/status/ABA12E/> >>>>>>>>> >>>>>>>>> -- >>>>>>>>> You received this message because you are subscribed to the Google >>>>>>>>> Groups "Algorithm Geeks" group. >>>>>>>>> To post to this group, send email to algogeeks@googlegroups.com. >>>>>>>>> To unsubscribe from this group, send email to >>>>>>>>> algogeeks+unsubscr...@googlegroups.com. >>>>>>>>> For more options, visit this group at >>>>>>>>> http://groups.google.com/group/algogeeks?hl=en. >>>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> -- >>>>>>>> Sunny Aggrawal >>>>>>>> B.Tech. V year,CSI >>>>>>>> Indian Institute Of Technology,Roorkee >>>>>>>> >>>>>>>> -- >>>>>>>> You received this message because you are subscribed to the Google >>>>>>>> Groups "Algorithm Geeks" group. >>>>>>>> To post to this group, send email to algogeeks@googlegroups.com. >>>>>>>> To unsubscribe from this group, send email to >>>>>>>> algogeeks+unsubscr...@googlegroups.com. >>>>>>>> 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 algogeeks@googlegroups.com. >>>>>>> To unsubscribe from this group, send email to >>>>>>> algogeeks+unsubscr...@googlegroups.com. >>>>>>> For more options, visit this group at >>>>>>> http://groups.google.com/group/algogeeks?hl=en. >>>>>>> >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> Sunny Aggrawal >>>>>> B.Tech. V year,CSI >>>>>> Indian Institute Of Technology,Roorkee >>>>>> >>>>>> -- >>>>>> You received this message because you are subscribed to the Google >>>>>> Groups "Algorithm Geeks" group. >>>>>> To post to this group, send email to algogeeks@googlegroups.com. >>>>>> To unsubscribe from this group, send email to >>>>>> algogeeks+unsubscr...@googlegroups.com. >>>>>> 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 algogeeks@googlegroups.com. >>>>> To unsubscribe from this group, send email to >>>>> algogeeks+unsubscr...@googlegroups.com. >>>>> For more options, visit this group at >>>>> http://groups.google.com/group/algogeeks?hl=en. >>>>> >>>> >>>> >>>> >>>> -- >>>> Sunny Aggrawal >>>> B.Tech. V year,CSI >>>> Indian Institute Of Technology,Roorkee >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "Algorithm Geeks" group. >>>> To post to this group, send email to algogeeks@googlegroups.com. >>>> To unsubscribe from this group, send email to >>>> algogeeks+unsubscr...@googlegroups.com. >>>> 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 algogeeks@googlegroups.com. >>> To unsubscribe from this group, send email to >>> algogeeks+unsubscr...@googlegroups.com. >>> For more options, visit this group at >>> http://groups.google.com/group/algogeeks?hl=en. >>> >> >> >> >> -- >> Sunny Aggrawal >> B.Tech. V year,CSI >> Indian Institute Of Technology,Roorkee >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Algorithm Geeks" group. >> To post to this group, send email to algogeeks@googlegroups.com. >> To unsubscribe from this group, send email to >> algogeeks+unsubscr...@googlegroups.com. >> 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 algogeeks@googlegroups.com. > To unsubscribe from this group, send email to > algogeeks+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/algogeeks?hl=en. > -- Regards, Arpit Sood -- You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to algogeeks@googlegroups.com. 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