Scythe by Neal Shusterman

Humanity has conquered death, and a benevolent artificial intelligence known as the Thunderhead governs a utopian world.

This book contains; alcohol (includes underage drinking), alternate gender/sexual ideologies, dark content, drugs (referenced), gore, murder of adults and children (called gleaning and a mass murder), profanity (minor), poisonings, self-inflected death (called splatting), sexual content, sexual harassment (minor), torture and violence
(graphic).