题解

#include<bits/stdc++.h>
using namespace std;
int a[100005],n,maxx,minn=100000000,t;
double ans;
int main()
{
    cin>>n;
    cout<<fixed<<setprecision(1);
    for(int i=1;i<=n;i++)
        cin>>a[i];
    for(int i=1;i<=n;i++)
	{
        cin>>t;
        if(minn>=a[i]-t)
			minn=a[i]-t;
        if(maxx<=a[i]+t)
			maxx=a[i]+t;
    }
	ans=(minn+maxx)*1.0/2;
    cout<<ans;
    return 0;
}