C#二分查找算法演示代码

// input array is assumed to be sorted
public int BinarySearch(int[] arr, int x)
{
    if (arr.Length == 0)
        return -1;

int mid = arr.Length / 2;

if (arr[mid] == x)
    return mid;

if (x < arr[mid])
    return BinarySearch(GetSubArray(arr, 0, mid - 1), x);
else
{
    int _indexFound = BinarySearch(GetSubArray(arr, mid + 1, arr.Length - 1), x);
    if (_indexFound == -1)
        return -1;
    else
        return mid + 1 + BinarySearch(GetSubArray(arr, mid + 1, arr.Length - 1), x);
}
 
}
public int[] GetSubArray(int[] arr, int start, int end)
{
    List<int> _result = new List<int>();
    for (int i = start; i <= end; i++)
    {
        _result.Add(arr[i]);
    }
    return _result.ToArray();
}       </pre>