C :

#include <stdio.h>
#include <stdlib.h>
#define maxn 2010
#define INF 1000000000
#define min(A,B) ((A)<(B))?(A):(B)
int A[maxn], dp[2][maxn];

int cmp(const void * a, const void * b) {
return ( *(int*)a-*(int*)b);
}

int main()
{
    int n, k;
    while(scanf("%d%d",&n,&k) != EOF) {
        if(n==0&&k==0) break;
        for(int i = 1;i <= n; i++)scanf("%d",&A[i]);
        for(int i = 0;i <= 1; i++){
            for(int j  = 0;j <= n; j++){
                dp[i][j]=INF;
            }
        }
        for(int i = 0;i < 2; i++)dp[i][0]=0;
        qsort(A+1,n,sizeof(int),cmp);
        for(int i = 2;i <= n; i++) {
            for(int j = k;j >= 1; j--){
                int temp = dp[1][j];
                dp[1][j]=min(dp[0][j-1]+(A[i-1]-A[i])*(A[i-1]-A[i]),dp[1][j]);
                dp[0][j]=temp;
            }
        }
        printf("%d\n",dp[1][k]);
    }
    return 0;
}