http://acm.fzu.

这个是我自己的代码可是总是不能提交，很容易超时的，因为一般的冒泡，选择，以及快速排序等方法都会超时的。
#include <stdio.h>
#include <algorithm>
using namespace std;
double a[1000000];
int main()
{
    int r,i,t,n,s;
    scanf("%d",&t);
      while(t--)
        {
          scanf("%d",&n);
            for(r=0;r<n;r++)
              scanf("%lf",&a[r]);
            sort(a,a+n);
            s=0;
            for(i=0;i<n;i+=2)
            {
                if(a[i]!=a[i+1])
                {
                    if(s==0)
                    {
                        printf("%.0lf ",a[i]);
                        i-=1;
                        s=1;
                    }
                    else
                    {
                        printf("%.0lf\n",a[i]);
                        break;
                    }
                }
            }         
        }
return 0;
}