AcWing 789. 数的范围

#include <bits/stdc++.h>
using namespace std;
const int N=1e6+10;
int q[N],mid;
int check_min(int ans[],int x,int l,int r){
  while(l<r){
      mid=l+r >> 1;
      if(q[mid]>=x) r=mid;
      else l=mid+1;
  }
  if(q[l]!=x) return -1;
  return l;  
}
int check_max(int ans[],int x,int l,int r){
   while(l<r){
      mid=l+r+1 >> 1;
      if(q[mid]<=x) l=mid;
      else r=mid-1;
  }
  if(q[l]!=x) return -1;
  return l;  
  return l;  
}
int main(){
    int n,m;
    scanf("%d%d",&n,&m);
    for(int i=0;i<n;i++)
        scanf("%d",&q[i]);
    while(m--){
        int x;
        scanf("%d",&x);
        cout<<check_min(q,x,0,n-1)<<" "<<check_max(q,x,0,n-1);
        printf("\n");
    }
    return 0;
}

AcWing 789. 数的范围