AcWing789.数的范围

题目链接

#include
using namespace std;
const int N = 100010;
int q[N];
int n, m;
int main()
{
	cin >> n >> m;
	for (int i = 0; i < n; i++)
		scanf("%d", &q[i]);
	while (m--)
	{
		int x;
		scanf("%d", &x);
		int l = 0, r = n - 1;
		while (l < r)
		{
			int mid = l + r >> 1;
			if (q[mid] >= x)
				r = mid;
			else
				l = mid + 1;
		}
		if (q[l] != x)
			cout << "-1 -1" << endl;
		else
		{
			cout << l << " ";
			l = 0, r = n - 1;
			while (l < r)
			{
				int mid = l + r + 1>> 1;
				if (q[mid] <= x)
					l = mid;
				else
					r = mid - 1;
			}
			cout << l << endl;
		}
	}
	return 0;
}