1 #include <cstring>
 2 #include <cstdio>
 3 #include <algorithm>
 4 #include <iostream>
 5 using namespace std;
 6 #define Max 2005
 7 int a[Max];
 8 int b[Max][Max];
 9 int k,n;
10 int sum=0,temp;
11 int func(int x,int y)
12 {
13     if(b[x][y]==0)
14         b[x][y]=(a[x]-a[y])*(a[x]-a[y]);
15     return b[x][y];
16 }
17 void dfs(int index,int s,int sep)
18 {
19     int i,j;
20     if(s>=sum)
21         return;
22     if(sep==(k+1))
23     {
24         if(s<sum)
25             sum=s;
26         return;
27     }
28     for(i=index;i<=n-(k-sep+1)*2+1;i++)
29     {
30         temp=func(i,i+1);
31         dfs(i+2,s+temp,sep+1);
32     }
33     return;
34 }
35 int main()
36 {
37     int i,j;
38     memset(b,0,sizeof(b));
39     freopen("in.txt","r",stdin);
40     while(scanf("%d%d",&n,&k)!=EOF)
41     {
42         sum=Max;
43         for(i=1;i<=n;i++)
44             scanf("%d",&a[i]);
45         sort(a+1,a+n+1);
46         dfs(1,0,1);
47         printf("%d\n",sum);
48     }
49 }

 1 dp[i][j]表示前i件物品取j对的最优解#include<cstdio>
 2 #include<cstring>
 3 #include<algorithm>
 4 using namespace std;
 5 #define N 2050
 6 #define ll int
 7
 8 ll dp[N][N];
 9 ll a[N];
10
11 int main()
12 {
13     ll n,k,i,j;
14
15     while(scanf("%d%d",&n,&k)!=EOF)
16     {
17         for(i=1;i<=n;i++)
18             scanf("%d",&a[i]);
19         sort(a+1,a+n+1);
20         memset(dp,0,sizeof(dp));
21         dp[2][1]=(a[2]-a[1])*(a[2]-a[1]);
22
23         for(j=1;j<=k;j++)
24             for(i=j*2;i<=n;i++)
25             {
26                 dp[i][j]=dp[i-2][j-1]+(a[i]-a[i-1])*(a[i]-a[i-1]);
27                 if(j*2<i)
28                 {
29                     dp[i][j]=min(dp[i-1][j],dp[i][j]);
30                 }
31
32
33             }
34         printf("%d\n",dp[n][k]);
35     }
36
37     return 0;
38 }