Former paramount leader of the People's Republic of China, Deng Xiaoping, once said: "it doesn't matter if the cat is black or white, any cat that can catch mice is a good cat".
Now, he was talking about communism and capitalism, but the point still stands: whether it's your (perhaps somewhat bloated and bourgeois) "capitalist code" or the more Spartan "communist code" of the model answers, as long as it gets the job done, that's the main thing.
With that said, you should still take a little time to observe (and hopefully learn from) the model answers after completing each algorithm challenge. Learning different perspectives, and perhaps some best practices, will do you a lot of favors in the future, especially in those cases where you find your code really isn't up to the job in terms of performance, readability, or some other relevant characteristic. In other words, when you find your code is neither a black nor a white cat but a platypus instead. And platypuses are terrible at catching mice.