hdu 1421 经典dp

 1 #include <algorithm>
 2 #include <cstring>
 3 #include <cstdio>
 4 using namespace std;
 5 
 6 const int N = 2001;
 7 const int M = 1001;
 8 int f[N][M];
 9 int c[N];
10 int n, k;
11 
12 int F( int i, int j )
13 {
14     if ( j * 2 > i ) return 999999999;
15     if ( i == 0 || i == 1 ) return 0;
16     return f[i][j];
17 }
18 
19 int main ()
20 {
21     while ( scanf("%d%d", &n, &k) != EOF )
22     {
23         for ( int i = 1; i <= n; i++ )
24         {
25             scanf("%d", c + i);
26         }
27         sort( c + 1, c + 1 + n );
28         for ( int i = 2; i <= n; i++ )
29         {
30             for ( int j = i / 2; j > 0; j-- )
31             {
32                 int d = ( c[i] - c[i - 1] ) * ( c[i] - c[i - 1] );
33                 f[i][j] = min( F( i - 1, j ), F( i - 2, j - 1 ) + d );
34             }
35         }
36         printf("%d\n", f[n][k]);
37     }
38     return 0;
39 }