@Algoose
Yes, but the algoritm is not correct since we are not covering the
condition where element is reused.
Ex ia=1 and ib=1
If we increment ia to 2 then there may be a case where A(1)+B(1) is
less than A(2)+B(1) but since 1 was denoted by ia which is now 2 hence
we will never be able to check this.
So algorithm ignores reuse of elements.


On Oct 27, 5:06 pm, Algoose chase <harishp...@gmail.com> wrote:
> @Dave,
>
> I believe in the first "if" clause ib must be incremented
>             in the "else if" clause ia must be incremented.
>
> is that right ?
>
>
>
> On Sat, Oct 16, 2010 at 6:21 PM, Dave <dave_and_da...@juno.com> wrote:
> > @Coolfrog$:
>
> > 1. No. It should be O(n + k log k) because finding the kth smallest
> > element of an array of size n is O(n), using the Median of Medians
> > algorithm; see
> >http://en.wikipedia.org/wiki/Median_algorithm#Linear_general_selectio...
> > .
>
> > 2. Assuming that the entries in A are distinct and so are the entries
> > in B, we can handle the equality of sums case:
>
> > find the smallest k elements of A and sort them into ascending order.
> > find the smallest k elements of B and sort them into ascending order.
> > ia = 1
> > ib = 1
> > output ia, ib, A(ia)+B(ib)
> > for n = 1 to k do
> >    if A(ia + 1) + B(ib) > A(ia) + B(ib + 1) then
> >        ia = ia + 1
> >        output ia, ib, A(ia)+B(ib)
> >     else if A(ia + 1) + B(ib) < A(ia) + B(ib + 1) then
> >        ib = ib + 1
> >         output ia, ib, A(ia)+B(ib)
> >     else // equality case
> >        ia = ia + 1
> >        ib = ib + 1
> >        output ia-1, ib, A(ia-1)+B(ib)
> >        output ia, ib-1, A(ia)+B(ib-1)
> >    end if
> > end for
>
> > Dave
>
> > On Oct 16, 6:20 am, "coolfrog$" <dixit.coolfrog.div...@gmail.com>
> > wrote:
> > > @Dave
> > >   1. should it not be O(k + klogk) ??
> > >   2. but u are not considering all the possible values... let k =3
> > >     like   i.  a1+b1
> > >             ii.  min( a1+b2, a2+b1)  upto these fine one of them will be
> > > chosen ...either ia or ib will increase.
> > >             iii. but know we have to take  remaining of step ii in to
> > > consideration along with
> > >                  a1+b3,a3+b1,a2+b3,a3+b2 ...
>
> > > On Fri, Oct 15, 2010 at 8:20 PM, Dave <dave_and_da...@juno.com> wrote:
> > > > @Coolfrog$: You don't have to sort the arrays. You only have to find
> > > > the k smallest elements in each and sort those k entries. This can be
> > > > done in O(n + k log k).
>
> > > > Algorithm:
> > > > find the smallest k elements of A and sort them into ascending order.
> > > > find the smallest k elements of B and sort them into ascending order.
> > > > ia = 1
> > > > ib = 1
> > > > output ia, ib, A(ia)+B(ib)
> > > > for n = 1 to k do
> > > >    if A(ia + 1) + B(ib) > A(ia) + B(ib + 1) then
> > > >        ia = ia + 1
> > > >    else
> > > >        ib = ib + 1
> > > >    end if
> > > >    output ia, ib, A(ia)+B(ib)
> > > > end for
>
> > > > Complexity O(n + k log k).
>
> > > > Dave
>
> > > > On Oct 15, 4:00 am, "coolfrog$" <dixit.coolfrog.div...@gmail.com>
> > > > wrote:
> > > > > @amod
> > > > >  as given   A->B      and    B->A are in sorted form...if not sort
> > them
> > > > in
> > > > > O(n log n).
> > > > > then
> > > > >       first suggestion  A1+B1
> > > > >    second suggestion  MIN( A1+B2 , B1+A2) ===> let it be B1+A2
> > > > >   third suggestion  MIN( A1+B2 , A1+B3, A3+B1,A2+B3, A3+B2)====> let
> > it
> > > > be
> > > > > A2+B3
> > > > >    and so on...
>
> > > > > @Dave what will be complexity of above solution...?
> > > > >     i think O(n log n) for sorting and second part (suggestions)
> > O(n)..
>
> > > > > Guys do correct me plz...
>
> > > > > On Thu, Oct 14, 2010 at 11:10 AM, Amod <gam...@gmail.com> wrote:
> > > > > > @Dave  You are partly correct.
>
> > > > > > If i ask for four minimum fares for the round trip then
> > > > > > first suggestion is what u said : sum the sum of the minimum cost
> > from
> > > > > > A to B and the minimum cost from B to A
> > > > > > after that we have to see which combination from both costs, sums
> > up
> > > > > > least
>
> > > > > > On Oct 14, 9:55 am, Dave <dave_and_da...@juno.com> wrote:
> > > > > > > @Amod. Isn't the minimum sum the sum of the minimum cost from A
> > to B
> > > > > > > and the minimum cost from B to A? What am I missing?
>
> > > > > > > Dave
>
> > > > > > > On Oct 13, 11:06 pm, Amod <gam...@gmail.com> wrote:
>
> > > > > > > > Hi
>
> > > > > > > > I think I forgot to mention that the SUM of the ROUND trip i.e.
> > > > A->B->A
> > > > > >  (sum = going + returning) should be least.
>
> > > > > > > > Please don't take into account any other thing like time and
> > > > > > > > availability.
> > > > > > > > So solution is not that straightforward.
>
> > > > > > > > Its like we have two arrays and we have to return least k sum
> > from
> > > > the
> > > > > > > > given arrays where we take one element from the first and one
> > from
> > > > > > > > second in the sum.
>
> > > > > > > > Cheers
> > > > > > > > Amod
>
> > > > > > > > On Oct 13, 2:26 pm, Shiyam code_for_life <
> > mailshyamh...@gmail.com>
> > > > > > > > wrote:
>
> > > > > > > > > When a user wants to choose to fly from A to B, suggest the
> > > > flight
> > > > > > > > > with lowest fare that's available, here its A1, if A1 is busy
> > > > then A2
> > > > > > > > > and so on
> > > > > > > > > Repeat the same for B to A.
>
> > > > > > > > > Am I missing something here?
>
> > > > > > > > > Complexity is O( (number of flights from A to B) + number of
> > > > flights
> > > > > > > > > from B to A) )
>
> > > > > > > > > Cheers
>
> > > > > > > > > 'Coding is an art'- Hide quoted text -
>
> > > > > > > > - Show quoted text -
>
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