Cruz' huge smash, whose genesis is broken down in this New York article. Here’s how it came to be:

Dr. Luke wrote “Dynamite”—sort of. It’s not entirely correct to say he writes his songs, at least not in the romanticized sense of a lonely dude scratching notes while strumming away on an acoustic guitar. Rather, he assembles songs. He curates them. He hears a song before it exists, then he figures out who can best help him bring that song into existence.

In this case, he created a basic beat track with his fellow producer Benny Blanco. (Dr. Luke has a slate of producers signed to his company, Prescription Songs.) The track was originally intended to go to the rapper Flo Rida, but it wasn’t a good fit as a rap song, so Luke sent it to Sweden, to Max Martin, who wrote half of a hook for the chorus. Luke wrote the other half, then sent that track to Bonnie McKee, a lyricist. Then Luke started looking for the right vocalist to attach.