in this case counting sort is inplace as how long the input array be ..the
auxilary array will be of soze 3 only.. and counting sort is stable too
On Thu, Jul 1, 2010 at 7:43 AM, Gene <gene.ress...@gmail.com> wrote:
> On Jun 30, 12:21 am, Sathaiah Dontula <don.sat...@gmail.com> wroe:
> > @Gene, Your logic is specific to 0, 1 and 2.
> >
> > Let me change the problem, there are three different symbols in an array,
> > separate them in O(n) with O(1) space.
> >
> > Thanks,
> > Sathaiah
>
> Well, your problem was specific to 0, 1, and 2.
>
> Arbitrary symbols are no different. You just create a lookup table
> that maps the symbols to 0,1,2 and look them up as needed. In the
> code below I made the lookup table s myself, but you could easily do
> it with a O(n) preprocessing pass.
>
> #include <stdio.h>
>
> #define M 3
>
> int idx(int *s, int ai)
> {
> int i = 0;
> for (i = 0; i < M; i++)
> if (s[i] == ai) return i;
> return -1;
> }
>
> void sort(int *s, int *a, int n)
> {
> int i, j, c[M];
> for (j = 0; j < M; j++) c[j] = 0;
> for (i = 0; i < n; i++) ++c[idx(s, a[i])];
> for (i = j = 0; j < M; j++)
> while (c[j]--)
> a[i++] = s[j];
> }
>
> int main(void)
> {
> int i, s[] = {'a','b','c'}, a[] =
> { 'c','c','a','b','a','b','c','a','c'};
> sort(s, a, sizeof a / sizeof a[0]);
> for (i = 0; i < sizeof a / sizeof a[0]; i++)
> printf("%c ", a[i]);
> printf("\n");
> return 0;
> }
>
> --
> You received this message because you are subscribed to the Google Groups
> "Algorithm Geeks" group.
> To post to this group, send email to algoge...@googlegroups.com.
> To unsubscribe from this group, send email to
> algogeeks+unsubscr...@googlegroups.com<algogeeks%2bunsubscr...@googlegroups.com>
> .
> For more options, visit this group at
> http://groups.google.com/group/algogeeks?hl=en.
>
>
--
With Regards,
Jalaj Jaiswal
+919026283397
B.TECH IT
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 algoge...@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.
