代码

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

评测结果