URAL 1306-Sequence Median(堆)

Input

Output

Sample

4
3
6
4
5

4.5

#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <vector>
#include <queue>
using namespace std;
const int maxn=250000;
int a[maxn/2+10];
int main()
{
    int n;double ans;
    while(scanf("%d",&n)!=EOF)
    {
       int num=0,x;
       for(int i=0;i<n/2+1;i++)
       scanf("%d",&a[i]);
       make_heap(a,a+n/2+1);
       for(int i=n/2+1;i<n;i++)
       {
           scanf("%d",&x);
           if(x<a[0])
           {
               pop_heap(a,a+n/2+1);
               a[n/2]=x;
               push_heap(a,a+n/2+1);
           }
       }
       if(n%2)
       {
		   ans=(double)a[0];
		   printf("%.1lf\n",ans);
       }
       else
       {
           ans=(double)a[0];
           pop_heap(a,a+n/2+1);
           ans+=(double)a[0];
		   printf("%.1lf\n",ans/2.0);
       }

    }
    return 0;
}