Be careful about focusing on brain teasers during interview sessions. In the early days at Microsoft they focused heavily on brain teaser interviews, and hired what was quickly seen to be an incredibly smart bunch of devs BUT much later seen to be a highly concentrated monoculture that over indexed on one set of skills at the expense of bringing in team members with other strengths. It took a lot of work to break away from that monoculture driving interview style and get the full set of skills and capabilities the company actually needed.

Not all smart people play chess, or know every line of Dr Who dialog, or are Makers, or like brain teasers.