#include <bits/stdc++.h>
#define MAXN 1005
using namespace std;
unsigned long long  f[MAXN][MAXN],w[MAXN];
int num[MAXN];
#define FZ(i,p)(f[i-1][p]+num[p+1]*num[p+1])
int i,p;
int que[MAXN],tail,head;
int n,m,j;
bool turnup(int i,int p1,int p2,int p3) //p1>p2>p3
{
	unsigned long long y1=FZ(i,p1),x1=num[p1],y2=FZ(i,p2), x2=num[p2], y3=FZ(i,p3), x3=num[p3];
	if((x2-x3)*(y1-y2)>(x1-x2)*(y2-y3))return 1;
	else return 0;
}int ii,nn;
int main()
{   scanf("%d",&nn);
	for(ii=1;ii<=nn;ii++)
	{
	scanf("%d%d",&n,&m);

	for(int i=1;i<=n;i++)
	{
		scanf("%d",&num[i]);
	}
	sort(num+1,num+n+1);
	for(i=1;i<=n;i++)
	  f[1][i]=(num[i]-num[1])*(num[i]-num[1]);
	  	for(i=1;i<=n;i++)
	  f[i][1]=0;
	for(int i=2;i<=m;i++){
 	 	head=tail=1;
  		que[tail++]=0;

  for(int j=1;j<=n;j++){
        while(head<tail-1&&FZ(i,que[head+1])-FZ(i,que[head])<2*num[j]*(num[que[head+1]]-num[que[head]]))
			head++;
	int k=que[head];
	f[i][j]=f[i-1][k]+(num[j]-num[k+1])*(num[j]-num[k+1]);
	while(head<tail-1&&turnup(i,j,que[tail-1],que[tail-2])==0)
	tail--;
	que[tail++]=j;
	}
	}
	printf("%I64d\n",f[m][n]);
	}
}

  

02-11 00:09