This is pretty much how it worked at the robotics company I worked at.
We would give them a whiteboard problem, but:
a) it was a simple, stupid problem in C (C++ was our implementation language, so thinking at byte level was an important skill)
b) we were very generous about minor mistakes like missing semicolons, etc.
c) we were very generous about "points for effort"; if they didn't make it through the problem but we saw that they were on the right track we might pass them. Total frauds outed themselves very early; they would produce between jack and squat in terms of actual code (a lot of bloviation though).
But again, most companies aren't that company, or your company. For most screening coding exercises, a correct answer (and even something like optimal algorithm complexity) is a must to pass the candidate.
We would give them a whiteboard problem, but:
a) it was a simple, stupid problem in C (C++ was our implementation language, so thinking at byte level was an important skill)
b) we were very generous about minor mistakes like missing semicolons, etc.
c) we were very generous about "points for effort"; if they didn't make it through the problem but we saw that they were on the right track we might pass them. Total frauds outed themselves very early; they would produce between jack and squat in terms of actual code (a lot of bloviation though).
But again, most companies aren't that company, or your company. For most screening coding exercises, a correct answer (and even something like optimal algorithm complexity) is a must to pass the candidate.