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Undoc'd Feature?
07-03-2022, 07:09 PM
Post: #11
RE: Undoc'd Feature?
(07-03-2022 06:24 PM)Wes Loewer Wrote:  What an interesting little program. I cannot begin to image what it is trying to calculate. Whatever it is doing, it repeats the exact same calculation 1000 times, and a[0] never gets initialized or used.

Do tell, what is this?

It solve 8-Queen puzzle. (code really need comments!)

Code:
if (!(t=a[x]-a[--y]) || x-y==abs(t)) { ...

a[] is array of 8x8 chess board, a[i] = j      → Queen at (i,j)
a[x] is the newly placed Queen,
a[y] are previously placed Queens, y = 1 .. x-1

Since we placed 1 Queen per row, there is no need to check horizontal attacks.
We only need to test vertical attacks (1st test), and diagonal attacks (2nd test)

I would have return actual board (8-digit number), instead of steps required to solve it.
We could have returned same steps, but not really solved anything ...

http://users.rcn.com/liusomers/nqueen_demo/nqueens.html
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Messages In This Thread
Undoc'd Feature? - toml_12953 - 07-03-2022, 03:42 AM
RE: Undoc'd Feature? - Wes Loewer - 07-03-2022, 09:14 AM
RE: Undoc'd Feature? - toml_12953 - 07-03-2022, 09:38 AM
RE: Undoc'd Feature? - Wes Loewer - 07-03-2022, 01:16 PM
RE: Undoc'd Feature? - Wes Loewer - 07-03-2022, 01:49 PM
RE: Undoc'd Feature? - toml_12953 - 07-03-2022, 02:18 PM
RE: Undoc'd Feature? - Wes Loewer - 07-03-2022, 06:24 PM
RE: Undoc'd Feature? - Albert Chan - 07-03-2022 07:09 PM
RE: Undoc'd Feature? - toml_12953 - 07-04-2022, 01:49 AM
RE: Undoc'd Feature? - toml_12953 - 07-04-2022, 09:41 AM
RE: Undoc'd Feature? - Wes Loewer - 07-04-2022, 03:40 PM
RE: Undoc'd Feature? - xerxes - 08-03-2022, 08:17 PM
RE: Undoc'd Feature? - parisse - 07-03-2022, 11:02 AM
RE: Undoc'd Feature? - Wes Loewer - 07-03-2022, 01:03 PM
RE: Undoc'd Feature? - parisse - 07-03-2022, 06:31 PM
RE: Undoc'd Feature? - Wes Loewer - 07-03-2022, 07:34 PM
RE: Undoc'd Feature? - jte - 07-08-2022, 03:15 AM
RE: Undoc'd Feature? - Wes Loewer - 07-08-2022, 05:00 AM
RE: Undoc'd Feature? - jte - 07-08-2022, 08:32 PM
RE: Undoc'd Feature? - Wes Loewer - 07-09-2022, 05:15 AM
RE: Undoc'd Feature? - RPNerd - 07-09-2022, 12:20 PM
RE: Undoc'd Feature? - Albert Chan - 07-09-2022, 05:10 PM
RE: Undoc'd Feature? - Wes Loewer - 07-10-2022, 05:22 AM
RE: Undoc'd Feature? - toml_12953 - 07-10-2022, 10:22 AM
RE: Undoc'd Feature? - RPNerd - 07-10-2022, 12:48 PM
RE: Undoc'd Feature? - Wes Loewer - 07-17-2022, 01:05 PM
RE: Undoc'd Feature? - jte - 07-31-2022, 02:12 AM
RE: Undoc'd Feature? - Wes Loewer - 07-31-2022, 06:43 PM
RE: Undoc'd Feature? - toml_12953 - 07-31-2022, 07:25 PM
RE: Undoc'd Feature? - Wes Loewer - 08-01-2022, 03:48 AM
RE: Undoc'd Feature? - ijabbott - 07-14-2022, 05:22 PM
RE: Undoc'd Feature? - toml_12953 - 07-10-2022, 05:36 PM
RE: Undoc'd Feature? - Albert Chan - 07-10-2022, 05:57 PM
RE: Undoc'd Feature? - Wes Loewer - 07-10-2022, 07:38 PM
RE: Undoc'd Feature? - ijabbott - 07-11-2022, 07:49 PM
RE: Undoc'd Feature? - RPNerd - 07-12-2022, 11:03 AM
RE: Undoc'd Feature? - ijabbott - 07-13-2022, 09:34 PM
RE: Undoc'd Feature? - Wes Loewer - 07-12-2022, 01:49 PM
RE: Undoc'd Feature? - ijabbott - 07-13-2022, 10:12 PM
RE: Undoc'd Feature? - toml_12953 - 07-13-2022, 10:50 PM
RE: Undoc'd Feature? - jte - 07-31-2022, 01:29 AM
RE: Undoc'd Feature? - Wes Loewer - 07-31-2022, 10:13 AM
RE: Undoc'd Feature? - OlidaBel - 07-04-2022, 09:11 AM
RE: Undoc'd Feature? - toml_12953 - 07-04-2022, 09:36 AM
RE: Undoc'd Feature? - ctrclckws - 07-13-2022, 12:44 PM
RE: Undoc'd Feature? - Wes Loewer - 07-13-2022, 08:01 PM



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