> When I first heard about the quantum search algorithm I thought it [O(sqrt(N)) run time] sounded impossible. I just couldn’t imagine any way it could be true.

> When I first heard about the quantum search algorithm I thought it [O(sqrt(N)) run time] sounded impossible. I just couldn’t imagine any way it could be true. It's curious to hear this from Nielsen himself. Personally, learning about Grover's algorithm was when I realised why "if you're not surprised by quantum mechanics, you cannot have understood a thing" (attributed to Bohr, I think).