数据结构与算法

折半查找

int BinarySearch(int len,int* arr,int x)
{
    assert(arr);
    int begin = arr[0];
    int end = len;
    while (begin < end)
    {
        int mid = ((end - begin) >> 2) + begin;
        if (arr[mid] < x)
        {
            begin = mid + 1;
        }
        else if (arr[mid]>x)
        {
            end = mid - 1;
        }
        else
        {
            return mid;
        }
        return -1;
    }
}