Definition: Near the extreme

as far as i can tell this must come from a programming context and near the extremes may from my understanding only mean near the outer boundaries:

reason:

in programming a list could be represented with Arrays.

at least in c Arrays are just pointers to the first Array element.

accessing the first element is therefor very fast (no Need to add an Offset to the address of the list to get to the list element's address before dereferencing the pointer)

why accessing the say last element should be fast as well i can not tell may be a feature of the language used. why accessing the say 3rd list element should be easy (in say a 50 List-Elements long list ) should be fast as well i can only wonder About (Maybe a Thing with caches)

where as i can understand that accessing the say 25th list element may require a) math to get to the address and b) may require a read from Memory because of a so called Cache-miss. this then takes compareably longer … Hope this answers the Question.