Author: Steffen Jakob
Date: 12:49:26 02/22/05
Go up one level in this thread
On February 22, 2005 at 15:43:44, Scott Gasch wrote:
>On February 22, 2005 at 09:20:31, Steffen Jakob wrote:
>
>>On February 22, 2005 at 08:35:07, Andrew Wagner wrote:
>>
>>>Hi all.
>>>I got sidetracked this morning by an interesting chess programming problem. It
>>>took me a couple hours, but I think I have a working algorithm -- haven't tested
>>>yet though. Anyway, I got to wondering if others would approach it the same way.
>>>So I thought I'd make a little competition of it. Post your code here, and I'll
>>>pick the program I like best and shower praise and adulation on its author. If
>>>people like this challenge, maybe I'll do one each month or something. Anyway,
>>>here's the one I did this morning:
>>>There are 64 x 63 = 4032 ways to put a black knight and white knoght both on a
>>>chess board. Write a program -- from scratch -- to generate FENs for each of
>>>these positions. The FENs should look something like: Nn6/8/8/8/8/8/8/8 w - - 0
>>>1.
>>>
>>>I think my code will wind up weighing in at around 60-70 lines of C. Can you do
>>>better?
>>
>>Here is a quick hack. Without comments, with place to optimize, also almost
>>untested, but shorter than yours ;-)
>>
>>
>>#include <iostream>
>>
>>int GetFile(int square) { return square & 7; }
>>int GetRank(int square) { return square >> 3; }
>>
>>int main(int argc, char** argv) {
>> for(int white_knight = 0; white_knight < 64; ++white_knight) {
>> for(int black_knight = 0; black_knight < 64; ++black_knight) {
>> if(white_knight == black_knight) {
>> continue;
>> }
>>
>> for(int rank = 7; rank >= 0; --rank) {
>> int n_empty = 0;
>> for(int file = 0; file <= 7; ++file) {
>> if(rank == GetRank(white_knight) && file == GetFile(white_knight)) {
>> if(n_empty > 0) {
>> std::cout << n_empty;
>> }
>> std::cout << "N";
>> n_empty = 0;
>> }
>> else if(rank == GetRank(black_knight) && file == GetFile(black_knight)) {
>> if(n_empty > 0) {
>> std::cout << n_empty;
>> }
>> std::cout << "n";
>> n_empty = 0;
>> }
>> else {
>> ++n_empty;
>> }
>> }
>> if(n_empty > 0) {
>> std::cout << n_empty;
>> }
>> if(rank != 0) {
>> std::cout << "/";
>> }
>> }
>> std::cout << " w - - 0 1" << std::endl;
>> }
>> }
>>
>> return 0;
>>}
>
>[ scott@wannabe:~/tmp ] % g++34 -O -S steffen.cpp ; wc -l steffen.s
> 557 steffen.s
Most of this code is because of using streams. If I replace them by printf,
define the GetXXX() functions inline and compile the code with gcc instead of
g++ I get 148 assembler lines.
Best wishes,
Steffen.
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