He can therefore he does. He must have had total control over the story line in making the movie. I feel the movie is much better but if Stephen King was disappointed with the changes I can see why, as there are so many. What he changed and how he did it is the most important clue to understanding the mystery of the film. After reading the book I've discovered something in the movie that's very well hidden, something that Stephen King has never said anything about even though he must have noticed it right away; Stanley Kubrick didn’t just randomly alter things from the novel (as many viewers think), he's reversed them. It’s like looking in a mirror where images are the reverse of what’s real. It's been noted how important mirrors are and parts of the movie are not just changed from the novel but are inverted mirror images (opposites) of what happens in the novel. I realized this with the colors of the two main vehicles in the story. In the novel they're brought to The Overlook in a red VW and saved on a yellow snowmobile. In the movie they're brought to The Overlook in a yellow VW and saved in a red Sno-cat. These color changes were meant to be noticed and this inversion can't be ignored, he's even done it with the plot. Stanley Kubrick has taken Stephen King’s novel and held it up to a mirror and what we're seeing in the movie is that reflection. A reflection where, in typical Kubrick fashion, just enough obvious changes are puzzlingly noticeable (The Hedge Maze and colors) and just enough is left alone (names and places), not being so obvious as to give it all away; Exactly like the numbers he wants us to notice.
If you would like to see some of what was altered in the movie click here and see.