score:3
But as I remember all laptop charger is universal, so I guess I don't need a voltage converter?
It should be printed on the charger - if it says something like "100-230V", you're fine. Usually this is the case for stuff that people are likely to travel with, such as laptops.
And I wonder does those hotel normally will have some power plug or converter that for traveller?
Hotels sometimes have sockets that admit multiple different plugs. If so, the US/Canadian plug will always be included. But such sockets are not always present, and often only in the bathroom, which is not a good place for a computer.
Or I have to buy one in Toronto Canada?
I would recommend this to be on the safe side. Plug adapters are cheap, shouldn't cost more than $5