<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title> test </title></head><body> <div><?php /*八皇后問題代碼實現 * * * *///根據前幾行的放置情況，判斷這一行是否合法function attack($n){ global $chess; for($i=1;$i<=$n-1;$i++){ if($chess[$n]==$chess[$i]+($n-$i)||$chess[$n]==$chess[$i]-($n-$i)||$chess[$n]==$chess[$i]){ return true; } } return false;}//輸出每種可能的解function display(){ global $chess; global $solution; echo " solution".sprintf("% 2d",$solution).":"; for($i=1;$i<=8;$i++){ $img = "<img src='../images/$chess[$i].png'/>"; echo $img; } echo "</br>"; $solution++; }//遞迴放置皇后function putchess($n){ global $chess; global $solution; for($i=1;$i<=8;$i++){ $chess[$n] =$i; if(!attack($n)){//沒有衝突 if($n==8){//已經放滿，輸出 display(); } else{ putchess($n+1); } }//if }//for }printf("八皇后問題的解如下：<br/>");$solution = 1;//$chess=array(1,2,3,4,5,6,7,8);putchess(1);echo "共有".($solution-1)."種不同的八皇后放置方法"; ?></div></body></html>
：
python版本的解法如下：
def conflict(state,nextX): nextY = len(state) for i in range(nextY): if(abs(state[i]-nextX)) in (0,nextY-i): return True return Falsedef queens(num = 8,state = ()): for pos in range(num): if not conflict(state,pos): if len(state) == num-1: yield (pos,) else: for result in queens(num,state+(pos,)): yield (pos,)+resultdef prettyprint(solution): def line(pos,length = len(solution)): return '. '*(pos) +'X '+'. '*(length-pos-1) for pos in solution: print line(pos)import randomprettyprint(random.choice(list(queens(8))))print len(list(queens(8)))
結果：
. . X . . . . . . . . . X . . . . . . . . . X . X . . . . . . . . . . X . . . . . X . . . . . . . . . . . . . X . . . . . X . . 92
Start building with 50+ products and up to 12 months usage for Elastic Compute Service
1 on 1 presale consultation
24/7 Technical Support 6 Free Tickets per Quarter Faster Response
Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.
A comprehensive suite of global cloud computing services to power your business
Payment Methods We Support
