A significant part of Stanley Kubrick's genius was his ability to translate a literary style into a visual one. It is demonstrated nowhere more brilliantly than in LOLITA and A CLOCKWORK ORANGE.
LOLITA is perhaps the more stunning accomplishment, in that Nabokov's style is complex and multi-layered. Yet Kubrick captures the effect of it in camera angles and movements, in timing and point of view.
The broadest layer of Nabokov's novel, the parable of the aging culture of Europe trying to revivify itself by debauching the seductive young culture of America, is really missing in the film. But everything else is there, despite the fact that the film departs from the exact events of the novel.
Not to say that the film depends on the novel. It stands by itself quite easily. But it succeeds brilliantly in conveying the ideas and feelings that are the core of the novel, and it does so in completely cinematic terms. If films are to be based on works of literature, this is the way to do it, and the way it is almost never done.
