在PHP里其中一个Permutation方程式。

在PHP里其中一个Permutation方程式。


<?php
$c = \" ABCD\";

$n = 4;
$i = 0;
echo \"<pre>\";
for ($m1=1;$m1<=$n;$m1++) {
   for ($m2=1;$m2<=$n;$m2++) {
   if ($m1 == $m2) {
   continue;       
   }
   for ($m3=1;$m3<=$n;$m3++) {
   if ($m1 == $m2 || $m2 == $m3 || $m3 == $m1) {
   continue;       
   }
   for ($m4=1;$m4<=$n;$m4++) {
   if ($m1 == $m2 || $m1 == $m3 || $m1 == $m4 || $m2 == $m3 || $m2== $m4 || $m3 == $m4) {                                   
   continue;       
   }
   $i++;
   $out[$i] = $c[$m1].$c[$m2].$c[$m3].$c[$m4];                     
   }       
   }              
   }
}

$out = array_unique($out);
print_r($out);
echo \"</pre>\";
?>



Array
(
   [1] => ABCD
   [2] => ABDC
   [3] => ACBD
   [4] => ACDB
   [5] => ADBC
   [6] => ADCB
   [7] => BACD
   [8] => BADC
   [9] => BCAD
   [10] => BCDA
   [11] => BDAC
   [12] => BDCA
   [13] => CABD
   [14] => CADB
   [15] => CBAD
   [16] => CBDA
   [17] => CDAB
   [18] => CDBA
   [19] => DABC
   [20] => DACB
   [21] => DBAC
   [22] => DBCA
   [23] => DCAB
   [24] => DCBA
)

什么是permutation?

全打得方程式。

被人打

。。。。
打你的头!方程式来的!

mabil and toto 全打得方程式~~ good ~

下面是引用super-tomato于2005-12-08 03:56 AM发表的:
代碼如果是哂靡粋€recursion的話,10枚金幣對初學者還算ok

有试过了,代码也有,但是,在速度方面不够快。

會不夠快??
那麼等一下我試試看

谢谢分享哦 Y^^

谢谢分享哦 Y^^

are u buying 4digit? mean that the possibility the number can be generated.