789. 数的范围

 

#include <iostream>
using namespace std;

const int N = 1e5 + 10;

int n, m;
int q[N];

int main()
{
    cin >> n >> m;
    for (int i = 0; i < n; ++ i)    cin >> q[i];
    
    while (m --)
    {
        int x;
        cin >> 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 << " ";
            
            int 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 << r << endl;
        }
    }
    
    return 0;
}