My friend the sudoku master

I sent my friend this sudoku puzzle, billed as the world’s hardest. I didn’t tell him where I got it from, figuring I’d reveal it once he was stumped.

Today he sent me back the solution. When I asked him how he’d found it, he said he solved the first half while sitting on the toilet, and the second half amidst work. It’d taken him just 30 minutes!

Update: Well, one of sharper eyed friends noticed that the puzzle illustrating the USA Today story isn’t the one the story’s about. Shame on me for not reading the fine text. This takes the oomph out of the whole thing.