If you learn all this and you can't solve LFU cache in 45 minutes, go back and study the parts about heapsort, red-black trees, and B trees. If you learn all t

If you learn all this and you can't solve LFU cache in 45 minutes, go back and study the parts about heapsort, red-black trees, and B trees. If you learn all this and you can't solve "integer to words", go back and do some more practical programming. Build your own blog in Django or something. If you learn all this and you can't solve "next permutation", well, yeah sometimes interviews ask you dumb theoretical stuff that you will never use in real life. Them's the breaks.