1 #include <stdio.h>
 2 #include <string.h>
 3 #include <stdlib.h>
 4 int dp[2100][1100];
 5 int a[2100];
 6 int n,k;
 7 int pow2(int a) {return a*a;}
 8 int min2(int a,int b) {return a<b?a:b;}
 9 
10 int cmp(const void* a,const void* b){
11   return *(int*)a-*(int*)b;
12 }
13 
14 int main(){
15   int i,j,l;
16   while(EOF != scanf("%d%d",&n,&k)){
17     for(i=1;i<=n;i++) 
18         scanf("%d",&a[i]);
19     qsort(a+1,n,sizeof(a[0]),cmp);
20     memset(dp,0,sizeof(dp));
21     for(i=2;i<=n;i++){
22       l=i/2;
23       for(j=1;j<=l;j++){
24         if(i==2*j)
25             dp[i][j]=dp[i-2][j-1]+pow2(a[i]-a[i-1]);
26         else 
27             dp[i][j]=min2(dp[i-1][j],dp[i-2][j-1]+pow2(a[i]-a[i-1]));
28       }
29     }
30     printf("%d\n",dp[n][k]);
31   }
32   return 0;
33 }