So my question is there any way to interact npc faster.

   What my script does is simply  "Use" item in my inventory and clicks on npc and repeat till inventory is full, but it clicks every 1-2 seconds and thats slow code that i use.

if (getInventory().isItemSelected()) {

npc.interact("use");

} else {

getInventory().interact("Use", "item name");

}

Please answer understandable way cuz im newbie.

Maybe something like this?

if (!inventory.isItemSelected()) {
    inventory.interact("Use", "item name");
    if (!new ConditionalSleep(2000) {
        @Override
        public boolean condition() {
            return inventory.isItemSelected();
        }
    }.sleep()) {
        return 10 + gRandom(5, 5);
    }
}
npc.interact("use");