题解

#include<bits/stdc++.h>
using namespace std;
int main() {
    int a;
    cin>>a;
    int n[114514],n1;
    for(int i=1;i<=a;i++){
        cin>>n[i];
    }
    int xx=0,cc=114514000;
    for(int i=1;i<=a;i++){
        cin>>n1;
        if(cc>n[i]-n1)cc=n[i]-n1;
        if(xx<n[i]+n1)xx=n[i]+n1;
    }
    double f=(cc+xx)*1.0/2;
    printf("%.1f",f);
    return 0;
}