When analyzing such codes, think about the steady state. Data streams in and out of the core from/to the memory hierarchy. Startup effects (i.e., how do the first elements of the data structures come into the CPU) are ignored. A large data structure that is updated will be read from memory and written back to memory eventually. A smaller data structure that fits into some cache may be reused from there (if there is actually reuse).
Think of the CPU as a data pump, not as a machine with cogwheels ticking away.
Hope this helps,
Georg.