It requires a single pass through the array, whereas the article suggests different approaches that all go through the array multiple times (or even O(n^2)). Fo

It requires a single pass through the array, whereas the article suggests different approaches that all go through the array multiple times (or even O(n^2)). For small lists this is probably ok, but for big lists it is a very slow approach. Edit: I would probably use a bloom filter for this.