还没写

#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;
const int N = 100010;
int n,q;
int a[N];

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

    return a[r]!=x?-1:r;
}
int rfind(int x)
{
    int l,r;
    l=0,r=n-1;
    int mid;
    while(l<r)
    {
        mid=(l+r+1)>>1;
        if(a[mid]<=x)
        {
            l=mid;
        }
        else 
        {
            r=mid-1;
        }
    }

    return a[r]!=x?-1:r;
}
int main()
{
    cin>>n>>q;
    for (int i = 0; i < n; i ++ ){
        cin>>a[i];
    }
    while(q--)
    {
        int k;
        cin>>k;
        cout<<lfind(k)<<" "<<rfind(k)<<endl;
    }
}