CCF 201903-1 小中大

#include <iostream>
#include <bits/stdc++.h>
#include <string>

using namespace std;

int main()
{
    int n;
    cin>>n;
    vector<int> v;
    for(int i=0;i<n;i++)
    {
        int temp;
        cin>>temp;
        v.push_back(temp);
    }
    double mid;
    int midint;
    int a1=v[0],a2=v[v.size()-1];
    if(n%2==0)
    {
        //if((v[(v.size()-1)/2]%2!=0&&v[(v.size()-1)/2+1]%2==0)||v[(v.size()-1)/2]%2==0&&v[(v.size()-1)/2+1]%2!=0)
            mid=(v[(v.size()-1)/2]+v[(v.size()-1)/2+1])*1.0/2;// 0 1 2 3
        //else
            //midint
    }
    else
    {
        midint=(v.at(v.size()/2));// 0 1 2
    }
    if(n%2==0)
    {
        int base=1;
        if(fabs(mid-(int)mid)<1e-9)
            base=0;
        if(a1<a2)
            cout<<a2<<" "<<setiosflags(ios::fixed)<<setprecision(base)<<mid<<" "<<a1<<endl;
        else
            cout<<a1<<" "<<setiosflags(ios::fixed)<<setprecision(base)<<mid<<" "<<a2<<endl;
    }
    else
    {
        if(a1<a2)
            cout<<a2<<" "<<midint<<" "<<a1<<endl;
        else
            cout<<a1<<" "<<midint<<" "<<a2<<endl;
    }
}