php FOR 循环优化有关问题

php FOR 循环优化问题
上次发个帖子没人跟,可能是问题不具体或者php基础编程人少或者太忙.............

我想从1-33选出6个不重复的号,然后写入数据库
现在选号过程PHP处理的很慢还总出错误,谁有兴趣帮我把下面的代码优化下:

PHP code

<!--

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--><?php $str=array(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33);
for($i=0;$i<28;$i++){
    for($j=$i+1;$j<33;$j++){
        for($k=$j+1;$k<33;$k++){
            for($l=$j+1;$l<33;$l++){
                for($m=$l+1;$m<33;$m++){
                    for($n=$m+1;$n<33;$n++){
                        echo "$str[i]|$str[j]|$str[k]|$str[l]|$str[m]|$str[n]|<br>";//显示效果,本想写入TXT文档在传如数据库.
                    }
                }
            }
        }
    }
}
?>

------解决方案--------------------

PHP code

$a  = range(1, 33);
$ar = combination($a, 6);

//求组合高效率的10移动法
function combination($numArr,$combineLen) {
  $numCt    = count($numArr);
  if($combineLen > $numCt) return;
  $bin    = str_pad('',$combineLen,'1');
  $bin    = str_pad($bin,$numCt,'0',STR_PAD_RIGHT);    
  $find    = $bin;
  $rs[]    = implode(' ',array_slice($numArr,0,$combineLen));
  $j        = 1;
  while(strrev($find) != $bin) {
    $k = explode('10',$find,2);
    $find = $find{0} === '0' ? strrev($k[0]).'01'.$k[1] : $k[0].'01'.$k[1];
    for($i=0;$i<font color="#e78608">------解决方案--------------------</font><br>

PHP code

[User:root Time:21:21:46 Path:/home/liangdong/php]$ php permutation.php 
Total time used : 9738642ms
[User:root Time:21:21:56 Path:/home/liangdong/php]$ cat permutation.php 
<?php $beg_time = microtime(true);
$beg_time *= 1000 * 1000;

$table = range(1, 33);
$temp = array();
$fp = null;

function _get_permutations($index, $num) {
        global $temp;
        global $total;
        global $table;
        global $fp;

        if ($num == $total) {
                global $perms;
                fwrite($fp, json_encode($temp) . PHP_EOL);
                return;
        }

        for ($ndx = $index; 33 - $ndx + $num >= $total; ++ $ndx) {
                $temp[$num] = $table[$ndx];
                _get_permutations($ndx + 1, $num + 1);
        }
}

function get_permutations($n = 6) {
        global $total;
        global $perms;
        global $fp;

        if ($n  33) {
                return false;
        }

        $total = $n;
        $fp = fopen("data.txt", "w");
        _get_permutations(0, 0);
        fclose($fp);
        return true;
}

get_permutations();

$end_time = microtime(true);
$end_time *= 1000 * 1000;
echo "Total time used : " . ($end_time - $beg_time) . "ms" . PHP_EOL;

?> <div class="clear">
                 
              
              
        
            </div>