On 26/03/2015 00:07, Ian Kelly wrote:
On Wed, Mar 25, 2015 at 2:31 PM, Marko Rauhamaa <ma...@pacujo.net> wrote:
It takes about 2 seconds for my Python program to find the answer but it
spends a total of 110 seconds to exhaust the problem space.
The analogous C program finished the whole thing in 200 milliseconds.
"Hard" for a human doesn't necessarily mean "hard" for a programmatic
solver in this case. Try your solver on this one:
$ cat sudoku2.dat
. . . 7 . . . . .
1 . . . . . . . .
. . . 4 3 . 2 . .
. . . . . . . . 6
. . . 5 . 9 . . .
. . . . . . 4 1 8
. . . . 8 1 . . .
. . 2 . . . . 5 .
. 4 . . . . 3 . .
I tried the first puzzle you posted, and it took about a second. I
then started running it on this one before I started typing up this
post, and it hasn't finished yet. While that was running, I then tried
running Norvig's solver on this puzzle, and it completed in about 0.07
seconds.
I tried my own brute-force solver, which normally takes 100msec, and it
took 2 seconds for your hard puzzle, about 20 times longer. (In a
language using a bytecode interpreter, not Python.)
Using Pypy, it took 90 seconds, instead of 1 second or so. So still
possibly faster than a human (faster than me certainly).
--
Bartc
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