题解

#include<bits/stdc++.h>
using namespace std;
int a[100001];
int main(){
int n,m;cin>>n>>m;
for(int i=1;i<=n;i++) cin>>a[i];
while(m--){
int x;cin>>x;
int l=1,r=n,ans=-1;
while(l<=r){
int mid=(l+r)/2;
if(a[mid]==x){
ans=mid;
l=n+1;
}
else if(a[mid]>x) r=mid-1;
else l=mid+1;
}
cout<<ans<<"\n";
}
return 0;
}