1 //HDOJ 3480
 2 #include<cmath>
 3 #include<vector>
 4 #include<cstdio>
 5 #include<cstring>
 6 #include<cstdlib>
 7 #include<iostream>
 8 #include<algorithm>
 9 #define rep(i,n) for(int i=0;i<n;++i)
10 #define F(i,j,n) for(int i=j;i<=n;++i)
11 #define D(i,j,n) for(int i=j;i>=n;--i)
12 #define pb push_back
13 #define CC(a,b) memset(a,b,sizeof(a))
14 #define SHOW_MEMORY(x) cout<<sizeof(x)/(1024.0)<<"KB"<<endl
15 using namespace std;
16 int getint(){
17     int v=0,sign=1; char ch=getchar();
18     while(!isdigit(ch)) {if(ch==‘-‘) sign=-1; ch=getchar();}
19     while(isdigit(ch))  {v=v*10+ch-‘0‘; ch=getchar();}
20     return v*sign;
21 }
22 const int N=10010,INF=~0u>>2;
23 const double eps=1e-8;
24 /*******************template********************/
25 int dp[5010][N],n,m,a[N],s[5010][N],ans;
26 void work(){
27     n=getint(); m=getint();
28     F(i,1,n) a[i]=getint();
29     sort(a+1,a+n+1);
30     F(i,1,m) F(j,1,n) dp[i][j]=INF;
31     F(i,1,n){
32         dp[1][i]=(a[i]-a[1])*(a[i]-a[1]);
33         s[1][i]=0;
34     }
35     F(i,2,m){
36         s[i][n+1]=n;
37         D(j,n,i)
38             F(k,s[i-1][j],s[i][j+1])
39                 if(dp[i-1][k]+(a[j]-a[k+1])*(a[j]-a[k+1])<dp[i][j]){
40                     s[i][j]=k;
41                     dp[i][j]=dp[i-1][k]+(a[j]-a[k+1])*(a[j]-a[k+1]);
42                 }
43     }
44     ans=dp[m][n];
45 }
46 int main(){
47     int T=getint();
48     F(i,1,T){
49         work();
50         printf("Case %d: %d\n",i,ans);
51     }
52     return 0;
53 }