Intersection of 2 arrays and doing operation on each - swift

Question

The code below successfully take a list of favourites names and matches it to a smaller list of names, and upon each match or mismatch, it creates a new data struct indicating if it was favourited. (However this seem to be (N^2) complexity)
listOfNames.forEach {
var faved = false
if namesFavorited.contains($0) {
faved = true
}
let model = DetailNameModel(name: $0, favorited: faved)
detailNameModelArray.append(model)
}
Is there a better way to do this that can SCALE to 10s of thousands say down to N or NLogN?

Answer 1

You can use Set collection. It provides efficient ways to interact with collections. More detail here.
Updated code:
let listOfNames: Set = ["name1", "name2", "name3", "name4", "name5", "name6", "name7", "name8"]
let namesFavorited: Set = ["name2", "name3", "name5", "name6", "name8", "name9", "name10", "name11"]
let nonFav = listOfNames.subtracting(namesFavorited) // O(m*n)
let fav = listOfNames.intersection(namesFavorited) // O(m*n)
var detailNameModelArray: [DetailNameModel] = []
let nonFavDetailNames = nonFav.map { // O(nonFav.count)
DetailNameModel(name: $0, favorited: false)
}
detailNameModelArray.append(contentsOf: nonFavDetailNames)
let favDetailNames = fav.map { // O(fav.count)
DetailNameModel(name: $0, favorited: true)
}
detailNameModelArray.append(contentsOf: favDetailNames)
print(detailNameModelArray) // O(fav.count)
You can generate a lot of data and compare my method and yours. I think my method will win.