二分查找模板

#include <iostream>
using namespace std;

const int N = 1e6 + 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;
}
}
}