Loop and onEnterFrame

1

hi, I’m trying to make a game, there’s lots of enemies and one player, here’s the problem:
when the player hits an enemy, I need to check which enemy it is. So I was thinking to use a loop that loop through all the enemy MC(enemy_0, enemy_1, enemy_2,enemy_3…):

 
var enemyNumber:Number = 50
for(var i:Number=0; i<=enemyNumber; i++){
    if(this.hitTest(_root["enemy"+i])){
        //code here......
    }
}

but later I thought this isn’t very effective, so I decided to put this ON EACH ENEMY:

 
this.onEnterFrame=function(){
    if(_root.playerClip.hitTest(this)){
        //code here......
    }
}

can you tell me which one is better?
thanks a lot