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The map you want is Abyss. You want all the computer opponents to be Zerg. Play as Protoss, and go for an early forge. Build a wall of photon cannons across the choke point in front of the natural expansion (make it very deep with cannons) and also put a few on the edges of your base. Expand early on and send all your probes to minerals in order to fund all of the cannons. Once you have a solid cannon wall 3-4 cannons deep, make 3-4 stargates and mass as many void rays as you can before your minerals run out.
You will be attacked a couple times, but the force should be almost entirely made up of roaches with only a few hydralisks / mutalisks. Once you have 12-15 voids or more, you'll be able to defend your base without any photon cannons (your wall will probably get demolished at least once anyway so that's a good thing).
The computers will resign over the course of the match until there are only one or two left. They should leave you alone aside from one or two attacks until this happens. When there's only one or two left, attack with your voids and mop up what's left. The only anti-air should be a few hydras, a couple queens, and the odd spore crawler.
It's so easy that I accomplished it on the first try without having even played Protoss before. It's a lot more difficult playing as another race against different types of computer opponents. My first attempt was to float to the corner island on Lava Flow and mass BCs. This is much, much easier.
This is a video of this strategy. It isn't me in the video (I'm fairly sure I did it in less time), but it's an adequate demonstration of what you need to do.