SDUT OJ 2862 勾股定理

#include<iostream>
using namespace std;
int a[1010];
void qsort(int a[],int l,int r)
{
	int x=a[l],i=l,j=r;
	if(l>=r)  return ;
	while(i<j)
	{
		while(i<j&&a[j]>=x) j--;
		a[i]=a[j];
		while(i<j&&a[i]<=x) i++;
		a[j]=a[i];
	}
	a[i]=x;
	qsort(a,l,i-1);
	qsort(a,i+1,r);
}
int main()
{
     int n,i,m,ans,j,k;
	 cin>>n;
	 while(n--)
	 {
		 cin>>m;
		 for(i=0;i<m;i++)
         cin>>a[i];
		 for(i=0;i<m;i++)
	     a[i]=a[i]*a[i];
		 qsort(a,0,m-1);
		 ans = 0 ;
         for(i = 0 ; i < m ; i++)
        {
            for(j = i+1 ; j < m ; j++)
            {
                k = a[i]+ a[j] ;
                int low = 0 , mid , high = m-1 ;
                while(low <= high)
                {
                    mid = (low + high) / 2 ;
                    if( a[mid] == k )
                        break;
                    else if( a[mid] < k )
                        low = mid + 1 ;
                    else
                        high = mid - 1 ;
                }
                if(a[mid] == k)
                    ans++ ;
            }
        }
        cout<<ans<<endl;
	 }
	 return 0;
}