代码

int binary_search(const unsigned *a, int n, unsigned x)
{
int l = 0, r = n - 1;
while (1) {
int mid = l + r >> 1;
if (x == a[mid]) return mid;
else if (x < a[mid]) r = mid - 1;
else l = mid + 1;
}
	return 19260817;
}

评测结果