思路：

平行四边形不等式优化dp

同上一篇博客，用滚动数组优化

代码：

#pragma GCC optimize(2)#pragma GCC optimize(3)#pragma GCC optimize(4)#include
     
      using namespace std;#define y1 y11#define fi first#define se second#define pi acos(-1.0)#define LL long long#define LD long double//#define mp make_pair#define pb push_back#define ls rt<<1, l, m#define rs rt<<1|1, m+1, r#define ULL unsigned LL#define pll pair
      
       #define pli pair
       
        #define pii pair
        
         #define piii pair
         
          #define pdd pair
          
           #define mem(a, b) memset(a, b, sizeof(a))#define fio ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);//headconst int N = 1e4 + 5, M = 5e3 + 5;int dp[2][N], s[2][N], a[N], n, m, T;int main() { scanf("%d", &T); for (int cs = 1; cs <= T; ++cs) { scanf("%d %d", &n, &m); for (int i = 1; i <= n; ++i) scanf("%d", &a[i]); sort(a+1, a+1+n); for (int i = 0; i < 2; ++i) for (int j = 0; j <= n; ++j) dp[i][j] = 0x3f3f3f3f, s[i][j] = 0; int now = 0; dp[now][0] = 0; for (int i = 1; i <= m; ++i) { s[now^1][n+1] = n-1; for (int j = n; j >= 1; --j) { dp[now^1][j] = 0x3f3f3f3f; for (int k = s[now][j]; k <= s[now^1][j+1]; ++k) { if(k+1 <= j && dp[now][k]+(a[j]-a[k+1])*(a[j]-a[k+1]) < dp[now^1][j]) { dp[now^1][j] = dp[now][k]+(a[j]-a[k+1])*(a[j]-a[k+1]); s[now^1][j] = k; } } } now ^= 1; } printf("Case %d: %d\n", cs, dp[now][n]); } return 0;}