assuming you get into Berkeley, that’s a good strategy.
CS 70 is an incredibly hard class, it does require a lot of work. Around 15 hours a week doing problem sets and studying, double or triple that before midterms and finals. But it is curved like crazy as well. For the Spring semester that just concluded, the median was around a 50% average on exams, good enough for a B+. A +0.5 standard deviation was an A-. CS 61A and CS61B are not curved, your grade is more or less on the 90/80/70 scale.