hey...bt this one works only in case given that the elements of the array are non-negative.
On Fri, May 27, 2011 at 2:30 PM, bhavana <[email protected]> wrote: > @sukhi : instead of using a map...use a boolean array elements of whoch r > initialised to false. > > Starting frm the first element of the array....if the number n is greater > than k ignore it....else mark a[n]=true and check if a[k-n]==true then we > get the required result .....bt if we reach the end of array without > entering the if condition the array doesnt contain any such pair. > > > On Fri, May 27, 2011 at 2:26 PM, sukhmeet singh <[email protected]>wrote: > >> @bhavana : Explain..!! >> as far as i get you is that it would be same as implementing map ...!! >> isn't ?? >> >> >> On Fri, May 27, 2011 at 2:16 PM, bhavana <[email protected]> wrote: >> >>> can be solved easily if the elements of the array lie in a limited range >>> which can b known beforehand...!! >>> >>> >>> On Fri, May 27, 2011 at 2:10 PM, Aakash Johari <[email protected]>wrote: >>> >>>> yes, you are right. map insertion takes O(log n) time. so if you know >>>> the upper bound of N, you can simply map the existence/non-existence of any >>>> particular element in an array. that will be in constant time (for query >>>> purposes) and O(n) time for preprocessing. >>>> >>>> >>>> On Fri, May 27, 2011 at 1:29 AM, sukhmeet singh <[email protected] >>>> > wrote: >>>> >>>>> @Dave nd @Akash can u explain a bit more.. I didn't get what u say.. >>>>> Inserting in a map takes O(log n) time !! >>>>> >>>>> On Fri, May 20, 2011 at 8:35 PM, Aakash Johari >>>>> <[email protected]>wrote: >>>>> >>>>>> @Dave: This is what is still a doubt to me. I have searched but >>>>>> couldn't get the info regarding this. >>>>>> >>>>>> >>>>>> On Fri, May 20, 2011 at 8:01 AM, Dave <[email protected]>wrote: >>>>>> >>>>>>> @Aakash: And tell me how map works. Is making an entry O(1) >>>>>>> regardless >>>>>>> of the value of the entry? For example, is it O(n) to map the >>>>>>> sequence >>>>>>> 1, 4, 9, 16, 25, ..., n^2? >>>>>>> >>>>>>> Dave >>>>>>> >>>>>>> On May 20, 9:39 am, Aakash Johari <[email protected]> wrote: >>>>>>> > @Dave: I got you. I will have to check before pushing the element >>>>>>> in map. >>>>>>> > >>>>>>> > >>>>>>> > >>>>>>> > >>>>>>> > >>>>>>> > On Fri, May 20, 2011 at 7:30 AM, Dave <[email protected]> >>>>>>> wrote: >>>>>>> > > @Aakash: Yeah, but try the same array with sum = 6 and see what >>>>>>> > > happens. >>>>>>> > >>>>>>> > > Dave >>>>>>> > >>>>>>> > > On May 20, 9:04 am, Aakash Johari <[email protected]> wrote: >>>>>>> > > > int main() >>>>>>> > > > { >>>>>>> > > > int a[10] = {5, 3, 10, 9, 8, 23, 11, 4, 12, 6}; >>>>>>> > > > int i; >>>>>>> > > > int sum; >>>>>>> > > > int flag = 0; >>>>>>> > >>>>>>> > > > map<int, int> m; >>>>>>> > >>>>>>> > > > for ( i = 0; i < 10; i++ ) { >>>>>>> > > > m[a[i]] = 1; >>>>>>> > > > } >>>>>>> > >>>>>>> > > > sum = 13; >>>>>>> > >>>>>>> > > > for ( i = 0; i < 10; i++ ) { >>>>>>> > > > if ( m[sum - a[i]] == 1 ) { >>>>>>> > > > flag = 1; >>>>>>> > > > break; >>>>>>> > > > } >>>>>>> > > > } >>>>>>> > >>>>>>> > > > if ( flag == 1 ) >>>>>>> > > > cout << a[i] << " " << sum - a[i] << endl; >>>>>>> > >>>>>>> > > > return 0; >>>>>>> > >>>>>>> > > > } >>>>>>> > > > On Fri, May 20, 2011 at 7:01 AM, hari <[email protected]> >>>>>>> wrote: >>>>>>> > > > > We can sort using STL sort function in main() before function >>>>>>> call of >>>>>>> > > > > arraysum(). >>>>>>> > >>>>>>> > > > > On May 20, 6:49 am, Gunjan Sharma <[email protected]> >>>>>>> wrote: >>>>>>> > > > > > First of all there is an infinite loop in this code.... >>>>>>> > > > > > Secondly it works only for sorted array. >>>>>>> > >>>>>>> > > > > > On Fri, May 20, 2011 at 7:16 PM, hari < >>>>>>> [email protected]> wrote: >>>>>>> > > > > > > In while loop have i,j which points first and last index >>>>>>> of array. >>>>>>> > > In >>>>>>> > > > > > > while loop, Check the sum of a[i],a[j], If >>>>>>> sum<k,increment i or >>>>>>> > > else >>>>>>> > > > > > > decrement j. Run the while loop till i<j.. >>>>>>> > >>>>>>> > > > > > > CODE: >>>>>>> > >>>>>>> > > > > > > int arraysum(int a[], int k, int i, int j) >>>>>>> > > > > > > while(i<j) >>>>>>> > > > > > > { >>>>>>> > > > > > > int p=0; >>>>>>> > > > > > > int b[10]; //to store index of selected nos >>>>>>> > > > > > > sum=a[i]+a[j]; >>>>>>> > > > > > > if (sum==k) >>>>>>> > > > > > > { >>>>>>> > > > > > > b[p++]=i;b[p++]=j; >>>>>>> > > > > > > } >>>>>>> > > > > > > elseif(sum<k) >>>>>>> > > > > > > i++; >>>>>>> > > > > > > else(sum>k) >>>>>>> > > > > > > j++; >>>>>>> > > > > > > return b; >>>>>>> > > > > > > } >>>>>>> > >>>>>>> > > > > > > On May 20, 4:38 am, amit <[email protected]> >>>>>>> wrote: >>>>>>> > > > > > > > given an array of integers, and an integer k, find out >>>>>>> two >>>>>>> > > elements >>>>>>> > > > > > > > from the array whose sum is k in O(n) time. if no such >>>>>>> element >>>>>>> > > exists >>>>>>> > > > > > > > output none. >>>>>>> > >>>>>>> > > > > > > -- >>>>>>> > > > > > > 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 >>>>>>> > > > > > Gunjan Sharma >>>>>>> > > > > > B.Tech IV year CSE >>>>>>> > >>>>>>> > > > > > Contact No- +91 9997767077 >>>>>>> > >>>>>>> > > > > -- >>>>>>> > > > > 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. >>>>>>> > >>>>>>> > > > -- >>>>>>> > > > -Aakash Johari >>>>>>> > > > (IIIT Allahabad)- Hide quoted text - >>>>>>> > >>>>>>> > > > - Show quoted text - >>>>>>> > >>>>>>> > > -- >>>>>>> > > 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. >>>>>>> > >>>>>>> > -- >>>>>>> > -Aakash Johari >>>>>>> > (IIIT Allahabad)- Hide quoted text - >>>>>>> > >>>>>>> > - Show quoted text - >>>>>>> >>>>>>> -- >>>>>>> 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. >>>>>>> >>>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> -Aakash Johari >>>>>> (IIIT Allahabad) >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> 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. >>>>> >>>> >>>> >>>> >>>> -- >>>> -Aakash Johari >>>> (IIIT Allahabad) >>>> >>>> >>>> >>>> >>>> -- >>>> 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. 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