5.2个人赛

B

随机序列

题意：算方差和极差，超简单

ac代码：

#include<iostream>

#include<cstdio>

#include<algorithm>

using namespace std;

#define ll long long

#define N 10004

int main()

{

   int t;

    cin>>t;

    while(t--){

    ll max1=-111,min1=60000;

        int n;

        cin>>n;

        ll a[N];

        double sum=0,sum1=0;

        for(int i=0;i<n;i++){

            cin>>a[i];

            sum+=a[i];

            max1=max(max1,a[i]);

            min1=min(min1,a[i]);

        }

        sum=sum*1.0/n;

       for(int i=0;i<n;i++){

        sum1+=(a[i]-sum)*(a[i]-sum);

       }

       cout<<max1-min1<<" ";

       printf("%.3lf\n",sum1/n);

    }

}

D

卡拉兹函数

本题最简单，相信都会

#include<iostream>
using namespace std;
int main()
{
int a;
cin>>a;
if(a%2==0)
cout<<a/2<<endl;
else cout<<3*a+1<<endl;
}