Why algorithm is important for every programmer?

Answer 1

Because you don't want to sit around trying to recreate the wheel when our species has spent a lot of time already figuring out things and sharing it with new generations that are born.

Answer 2

Its a step by step guide to solve a particular problem. They are just as important as data structures as well.

like the old saying think twice code once. Have a plan before attack it will save you errors and annoying bugs later on.