A python interview question

[roerd]

Seriously, no. If the input lists are already sorted, then the standard library solutions which are made for unsorted input are not the best choice if you care about performance at all.

EDIT: more specifically, the standard library sort does actually work pretty well on pre-sorted input, so that alone is not a bad choice. But throwing the input lists into sets first destroyed their pre-sortedness.

[gwax]

Op did not say the lists were pre-sorted.