ZOJ 3499 Median(数学)

#include <algorithm>
#include <iostream>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <string>
#include <vector>
#include <queue>
#include <stack>
#include <cmath>
#include <ctime>
#include <list>
#include <set>
#include <map>

using namespace std;
typedef long long ll;
#define PB push_back
#define UB upper_bound
#define LB lower_bound
#define MP make_pair
#define pii pair<int,int>
#define vi vector<int>
#define vii vector<vi>
#define mst(x,y) memset(x,y,sizeof(x))
#define fr(x) freopen(x,"r",stdin)
#define fw(x) freopen(x,"w",stdout)
#define iin(x) scanf("%d",&x)
#define complete_unique(a) a.erase(unique(a.begin(),a.end()),a.end())
#define sp system("pause")
#define INF 1e9
#define MAXN 100005
#define PI acos(-1.0)
#define eps 1e-10
const int MOD = 1e9 + 7;

double a[500+20];

int main()
{
int T;
cin>>T;
while(T--)
{
int n;
cin>>n;
for(int i=0;i<n;i++)
{
scanf("%lf",&a[i]);
}
sort(a,a+n);
if(n&1)
{
printf("%.3lf\n",a[n/2]);
}
else
{
printf("%.3lf\n",(a[n/2]+a[n/2-1])/2.0);
}
}
return 0;
}