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<?php
function CreateAmida($org)
{
    if (!ctype_alnum($org) ||
        count(array_unique(str_split($org))) != count(str_split($org))) {
        return NULL;
    }
    $bridge_num = strlen($org)-1;
    $p = $org;
    $step = array();
    while (1) {
        $chg = FALSE;
        $step_buf = array_fill(0, $bridge_num, ' ');
        for ($i = 0; $i < $bridge_num; $i++) {
            if ($p[$i] > $p[$i+1]) {
                $sub = array($p[$i]=>$p[$i+1], $p[$i+1]=>$p[$i]);
                $p = strtr($p, $sub);
                $step_buf[$i] = '-';
                $i++;
                $chg = TRUE;
            }
        }
        if ($chg) {
            $step[] = '|'.implode('|', $step_buf).'|';
        } else {
            break;
        }
    }
    $res = implode(' ', str_split($p))."\n";
    $res .= implode("\n", array_reverse($step))."\n";
    $res .= implode(' ', str_split($org))."\n";
    return $res;
}
?>