4 ms·

Can you elaborate more on quick sort? What does that achieve? Why does insertion sort not work, and why does it require cunningness?

SimonPStevens 5y ago
No op, but I think I understand what they are getting at. With a quicksort you take one item and compare it one at a time to every other item by just asking this question "does this come before or after". Then you repeat that process with each side. But with insertion sort you take each new item and ask the question "where does it go in this already ordered list". Although these are logically essential the same thing, and certainly have the same result, it's the way the question is framed that makes the quicksort approach often the easier question to answer when trying to decide on a priority order. Both require a little cunning because you have to get the other person to "forget" that they are essentially prioritising a large list and focus on the easier question of the individual step in the sort algorithm. That's easier with quicksort because the question is very small and isolated, but with insertion sort you are constantly looking at the larger list in order to find the insertion point.
SonOfLilit 5y ago
Not GP, but I assume they mean "choose a random task, partition all other tasks on more/less important than it, recurse (probably only for the 'more' taskset)". This doesn't really feel like a full sort of tasks. Insertion-sorting the tasks does, and so would trigger the "oh no all of these are important" reflex sooner.
Tade0 5y ago
The other replies explained this really well, but I'd add that the effect typically is dropping requirements which only seemed important at the time. Often happens once the reduced scope is delivered and new tasks arrive and it occurs to the stakeholders that the current state is "good enough for now". I usually do one comparison per meeting - regardless of the topic at hand.

SimonPStevens 5y ago

No op, but I think I understand what they are getting at. With a quicksort you take one item and compare it one at a time to every other item by just asking this question "does this come before or after". Then you repeat that process with each side. But with insertion sort you take each new item and ask the question "where does it go in this already ordered list". Although these are logically essential the same thing, and certainly have the same result, it's the way the question is framed that makes the quicksort approach often the easier question to answer when trying to decide on a priority order. Both require a little cunning because you have to get the other person to "forget" that they are essentially prioritising a large list and focus on the easier question of the individual step in the sort algorithm. That's easier with quicksort because the question is very small and isolated, but with insertion sort you are constantly looking at the larger list in order to find the insertion point.

SonOfLilit 5y ago

Not GP, but I assume they mean "choose a random task, partition all other tasks on more/less important than it, recurse (probably only for the 'more' taskset)". This doesn't really feel like a full sort of tasks. Insertion-sorting the tasks does, and so would trigger the "oh no all of these are important" reflex sooner.

Tade0 5y ago

The other replies explained this really well, but I'd add that the effect typically is dropping requirements which only seemed important at the time. Often happens once the reduced scope is delivered and new tasks arrive and it occurs to the stakeholders that the current state is "good enough for now". I usually do one comparison per meeting - regardless of the topic at hand.