Array Contains Performance

Question

I have a program which works with arrays and at some point I have to check if a lsit of values are inside an array, the function that does this takes about 70% of the program CP

Answer 1

Instead of shuffle, you can generate the possible values in a list and take values at random positions. That way you can start using the items even before the whole row is generated:

    IEnumerable RandomRange(int count) {
        var random = new Random();
        var list = new int[count];
        for (int i = 0; i < count; i++) list[i] = i;

        while (count > 0) {
            var i = random.Next(count);
            yield return list[i] ;
            list[i] = list[--count];
        }
    }

sample use:

foreach(var item in RandomRange(10))
    // ...