BinarySearch.cs

using BenchmarkDotNet.Attributes;

namespace BinarySearch.Benchmark;

[MemoryDiagnoser]
public class SearchBenchmark
{
    private static readonly int[] Numbers = Enumerable.Range(1, 1_000_000).ToArray();

    [Params(333_333, 777_777)]
    public static int NumberToFind { get; set; }

    [Benchmark]
    public int BinarySearch_Bcl()
    {
        var index = Array.BinarySearch(Numbers, NumberToFind);

        return index;
    }

    [Benchmark]
    public int BinarySearch()
    {
        var index = BinarySearch(Numbers, NumberToFind);

        return index;
    }

    [Benchmark]
    public int BinarySearch_Shift()
    {
        var index = BinarySearch_Shift(Numbers, NumberToFind);

        return index;
    }

    private static int BinarySearch(int[] array, int numberToFind)
    {
        int low = 0;
        int high = array.Length - 1;

        while (low <= high)
        {
            int mid = low + (high - low) / 2;

            if (array[mid] == numberToFind)
            {
                return mid;
            }

            if (numberToFind < array[mid])
            {
                high = mid - 1;
            }
            else
            {
                low = mid + 1;
            }
        }

        return -1;
    }

    private static int BinarySearch_Shift(int[] array, int numberToFind)
    {
        int low = 0;
        int high = array.Length - 1;

        while (low <= high)
        {
            int mid = low + ((high - low) >> 1);

            if (array[mid] == numberToFind)
            {
                return mid;
            }

            if (numberToFind < array[mid])
            {
                high = mid - 1;
            }
            else
            {
                low = mid + 1;
            }
        }

        return -1;
    }
}