$type = str_replace("t","t",$type);
$type = str_replace("index.php?page=topic&show=1&id=","t",$type);

RewriteRule ^topic([0-9]+).html t$1 [L]
RewriteRule ^topic([0-9]+)&password=(.*)&count=([0-9]+) t$1&password=$2&count=$3 [L]
RewriteRule ^topic([0-9]+)&count=([0-9]+) t$1&count=$2 [L]
RewriteRule ^topic([0-9]+)&last_post=1&count=([0-9]+) t$1&last_post=1&count=$2 [L]
RewriteRule ^topic([0-9]+) t$1 [L]