Not necessary, interviewed for a Sr Engineer role where I clearly impressed the CTO, but didn't do that great on a stupid coding exercise. And that was not even a requirement for the job, and I told them that was not my strongpoint. I'd done my homework on the company, they had bottlenecks, which I suggested a solution for, and they were pretty blown away. But like other folks here pointed out, all companies want are folks who can crack the coding exercise, everything else is a hogwash.