Yes, read my first post
On Wed, Feb 22, 2012 at 10:19 AM, atul anand <[email protected]>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 <[email protected]>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 <[email protected]>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 <[email protected] >>> > 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 <[email protected]> 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 < >>>>> [email protected]> 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 <[email protected]> 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 [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. >>>>>>> >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> 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 [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. >>>>> >>>> >>>> >>>> >>>> -- >>>> 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 [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. >>> >> >> >> >> -- >> 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 [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. > -- 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 [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.
