题解 | 牛牛的数学作业

#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
using namespace std;
int N = 1001;
int T = 10e5;
void solve()
{
    int a[N];
    int n;
    cin >> n;
    int imax = 0;
    int imin = T;
    int sum = 0;
    double sum_2 = 0;
    for(int i = 0; i < n; i++)
    {
        cin >> a[i];
        imax = max(imax, a[i]);
        imin = min(imin, a[i]);
        sum += a[i];
    }
    double avg = 1.0*sum / n;
    for(int i = 0; i < n; i++)
    {
        sum_2 += pow((1.0*a[i] - avg) ,2) ;
    }
    double ans = sum_2 * 1.0 / n;
    cout << (imax - imin) <<" ";
    printf("%.3f\n",ans); 
}
int main() {   
    int t;
    cin >> t;
    while(t--)
    {
        solve();
    }
    return 0;
}