#include <cstdio>
#include <iostream>
#include <algorithm>
#include <queue>
#include <cmath>
#include <cstring>
#include <stack>
#include <set>
#include <map>
#include <vector>
using namespace std;
#define INF 0x2fffffff
#define LL long long
#define MAX(a,b) ((a)>(b))?(a):(b)
#define MIN(a,b) ((a)<(b))?(a):(b)
double a[30];
double b[30];
double c[30];
double dp[1 << 21];
double d[30][30];
int n,m;
double ans;
void fun(int status,int cur,int qu){
if(qu == m){
ans = max(ans,dp[status]);
return;
}
if(cur > n){
return ;
}
double c = 0;
for(int i = 0;i < cur;i++){
if(status&(1<<i)){
c += d[cur][i];
}
}
dp[status|(1<<cur)] = dp[status] + c;
fun(status|(1<<cur),cur+1,qu+1);
fun(status,cur+1,qu);
}
int main(){
while(cin >> n >> m){
for(int i = 0;i < n;i++){
cin >> a[i] >> b[i] >> c[i];
}
memset(d,0,sizeof(d));
for(int i = 0;i < n;i++){
for(int j = 0;j < n;j++){
d[i][j] = (a[i]-a[j])*(a[i]-a[j]) + (b[i]-b[j])*(b[i]-b[j]) + (c[i]-c[j])*(c[i]-c[j]);
}
}
memset(dp,0,sizeof(dp));
ans = 0;
fun(0,0,0);
printf("%.6f
",ans);
}
return 0;
}
状压搜索
点击看题