i need a good gaming laptop with a good processor and graphics that will run minecraft smoothly and will last a long time, my budget is 300-400 dollars.
For that price range you will be extremely limited in your options. However you are not completely out of options. Currently your best option will be something with an AMD APU powering it as it's dedicated graphics solution is better than the current offerings from Intel and their HD 4000. You more than likely will not be able to find anything with an A10-4600m in it but there are a couple of options with the A8-4500m.
Those are two options that I could find with a quick search. I do know from personal expierence that the A10-4600m can handle Minecraft with view distance set to far. The biggest thing I can suggest if you do go with an AMD APU is as soon as you can upgrade the ram to 2 x 4 Gb @ 1600 Mhz as it will help with the APU graphics.