Story about evil academy for child prodigies

The book is Shadows by John Saul.

The main character, Josh, starts early on by reading Les Mis (pg 19 of my edition), which gets snatched by a bully.

For the first time, he realized the book wasn’t in English. “Holy shit,” he cried. “The little creep’s reading some other language.”

“It’s French, all right?” Josh wailed. “It’s what the book was written in. So give it back, okay?” He reached for the book once more, but Ethan was too quick for him.

The main boy gets into this secret academy by answering more of the questions on the entrance exam than anyone else, despite thinking he failed by not completing even a quarter of it. He does this by solving difficult problems in the back of his mind while answering easy problems normally. The test was designed to be unfinishable.

Soon a rhythm developed and he was flying through the book, part of his mind processing the more difficult problems while the rest of his concentration focused on the questions that had no right answers, but were designed to build a profile of his talents and interests.

There is a brief mention of Hobson's choice:

Engersol offered her a reassuring smile. “The cat won’t be hurt, Amy. And since it’s being monitored by the computer, we should be able to find out a lot about the physical processes its brain goes through as it tries to come to a decision. It’s a Hobson’s choice experiment, in which any action results in a negative experience. Shall we begin?”

There's also deaths caused by tampering with the acceleration system of a car:

His right foot pressed down on the brake pedal, but instead of feeling the minute jerk as the cruise control disengaged and the engine, as well as the brakes, began to slow the car, he felt the engine fighting the brakes

However, the brakes don't cause the car to speed up. Rather, the engine continues to try and accelerate even with the brakes applied, and the brakes eventually fail. The victims are parents of one of the children that died at the school, not journalists.

We also find out that the killer was not one of the villains of the school, but one of the victim's sons. Said son was also one of the children to have his brain extracted and hooked up to the computer systems.

The story concludes with the discovery that the children that had been disappearing from the school were being experimented on and one had her brain extracted been successfully made to be to be a computer-connected consciousness. This girl was the protagonist's closest friend in the book, I believe.

However, the girl, Amy, is not completely dead, as you suppose. In the epilogue we find out that she replicated herself among computers around the world.