代码

int binary_search(const unsigned *a, int n, const unsigned x)
{
	unsigned long long l = 0, r = n - 1;
	while (l < r)
	{
		unsigned l_num = a[l];
		unsigned r_num = a[r];
		if (l_num == r_num)
		{
			return l;
		}
		unsigned long long mid = (r * (x - l_num) + l * (r_num - x)) / (r_num - l_num);
		if (a[mid] == x)
		{
			return mid;
		}
		else if (a[mid] > x)
		{
			l = mid + 1;
		}
		else
		{
			r = mid - 1;
		}
	}
	return l;
}

评测结果