题解 | 牛牛的数学作业

#include <climits>
#include <iostream>
#include<algorithm>
#include<iomanip>
#include <vector>
using namespace std;

int main() {
    int T;
    cin>>T;
    while(T--){
    int a;
    cin>>a;
    vector<long long> t1(a);
   
    long long x1 = 0;
    long long s1 = 0;
    long long x2 =LLONG_MAX;
    for(int i = 0;i < a;i++){
        cin>>t1[i];
        x1 = max(x1,t1[i]);
        x2 = min(x2,t1[i]);
        s1 += t1[i];
    }
    
    double  ans1 = 0.000;
    double avg = (double)s1 / a;
    for(int i= 0;i < a;i++){
    ans1 += ((double)t1[i] - avg) * ((double)t1[i] - avg);
    }
    //long double ans2 = (double)ans1 / (double)a;
    cout<<x1 - x2<<" "<<fixed<<setprecision(3)<<ans1 / (double)a<<endl;
    }

}
// 64 位输出请用 printf("%lld")