Been hacking frontend for a while, know most of the perks and tricks of css and html, have implemented countless of projects with angularjs, have even created jquery plugins and gulp packages, have won hackatons in UX design.... Still, a SFO company turned me down for a front end dev position cause I could not find the K most frequent words in an array in O(n) time complexity...

Last hackaton (and first) I participated in was a disaster.
In the end our team was the only team, but there were other hackatons as well so in the end they just judged all the different hackatons as if they were all the same and that's the story of my team not winning 25k$