Convert mutable 2D array of pairs to a static 2D array in kotlin

How can I convert:
mutableListOf<MutableList<Pair<Int, Int>>>
To a:
Array<Array<Pair<Int,Int>>>

I’m pretty new in the language of Kotlin, I thought that I can loop for the entire 2D array and put the values in the new one, but I was wondering if there’s another faster solution

>Solution :

I thought that I can loop for the entire 2D array and put the values in the new one

You can’t actually explicitly "loop". When you create an Array of non-null elements in Kotlin you have to specify the default value at each index. So all you have to do is specify each element of the list:

// suppose list is a MutableList<MutableList<Pair<Int, Int>>>
// create an array of list.size...
Array(list.size) { i ->
    // where the element at index i is another array with size "list[i].size"
    Array(list[i].size) { j -> 
        // and the element at index j of this array is "list[i][j]"
        list[i][j] 
    }
}

This is pretty much as fast as you can get in terms of execution time.

If you mean "fast" as in less typing, you can do:

list.map { it.toTypedArray() }.toTypedArray()

This first converts the inner lists to arrays, creating a List<Array<Pair<Int, Int>>>, and then converts that list to an array.