Quip reject

Just got reject from quip. Though they said feedback was positive but there were some glitches in laptop n whiteboarding n they will pass this time. Bar is really really high. I answered every question, though in one round interviewer gave me hint to think in graph terms but i was thinking in different direction, later i wrote the code well. Overall i dont want to rant, but i loved the experience n will improve more on coding n problem solving means more leetcoding. I have fb n google onsite next week. Hope to do better. Any quick tips, which i might have overlooked?