题解 | 牛牛的数学作业

#include <stdio.h>

int main() {
    int T;
    scanf("%d",&T);
    while(T--){
        int n;
    scanf("%d",&n);
    int arr[10000];
    for(int i=0;i<n;i++){
        scanf("%d",&arr[i]);
    }
    int max=arr[0];
    int min=arr[0];
    for(int i=1;i<n;i++){
        if(arr[i]>max){
            max=arr[i];
        }else if(arr[i]<min){
            min=arr[i];
        }
    }
    int jicha=max-min;
    long long sum=0;
    for(int i=0;i<n;i++){
        sum+=arr[i];
    }
    double average=(double)sum/n;
    double sum1=0.0;
    for(int i=0;i<n;i++){
    sum1+=(arr[i]-average)*(arr[i]-average);
    }
    double fangcha=sum1/n;
    printf("%d %.3f\n",jicha,fangcha);
    }
    return 0;
}