Target Time/Memory Are Confusing

[EugenHotaj]

For some of the puzzles, the target memory (and time) are impossible to satisfy. E.g. for puzzle 0, I spent some time trying to get from 2621440 to under the target of 2600000 until I realized that the solution notebook also takes 2621440 memory. A few other puzzles have similar impossible memory / time targets.

Should we update the targets to what can actually be achieved in practice? Happy to send a PR if you agree.