How to check if an array contains any item of another array

Question

Given 2 int arrays e.g, foo and bar, what\'s the most efficient way to check that the array bar contains at least one item that foo contains. should re

Answer 1

For one-shot random-array approach, your method seems to be the fastest. There are methods that would make it way more efficient if one or both matrices are sorted, their upper/lower bounds are known, or one of them changes way more rarely than the other one and you perform many checks. Thing is you can prepare various hashes, indices and hints that will optimize the search to nearly nothing, but the process of indexing alone will usually take more than a single search.