hdu 2489 最小生成树状态压缩枚举

思路：

直接状态压缩暴力枚举

#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cstring>
#define Maxn 30
#define inf 10000000
using namespace std;
int ans,n,m;
int c,d;
int map[Maxn][Maxn];
int lis[Maxn],node[Maxn];
int val[<<],sum[<<];
int main()
{
    int i,j;
    while(scanf("%d%d",&n,&m),n||m){
        memset(val,,sizeof(val));
        memset(sum,,sizeof(sum));
        c=,d=;
        for(i=;i<=n;i++)
            scanf("%d",&node[i]);
        memset(map,,sizeof(map));
        for(i=;i<=n;i++){
            for(j=;j<=n;j++){
                scanf("%d",&map[i][j]);
            }
        }
        int N=<<n;
        N-=;
        int cnt=;
        val[]=;
        for(i=;i<=n;i++)
            val[<<i]=;
        for(i=;i<=N;i++){
            cnt=;
            for(j=;j<n;j++){
                if(i&(<<j)) lis[++cnt]=j+,sum[i]+=node[j+];
            }
            if(cnt>m) continue;
            if(cnt==m)
            {
                int a=val[i],b=sum[i];
                if(a*d<c*b){
                    ans=i;
                    c=a;
                    d=b;
                }
            }
            int temp;
            for(j=;j<n;j++){
                if(((<<j)&i)==){
                    temp=inf;
                    for(int k=;k<=cnt;k++){
                        temp=min(temp,map[j+][lis[k]]);
                    }
                    val[i|(<<j)]=min(val[i]+temp,val[i|(<<j)]);
                }
            }
        }
        int num=;
        for(j=;j<n;j++)
            if((<<j)&ans){
                printf("%d",j+);
                if(num!=m)
                    printf(" ");
                num++;
            }
        printf("\n");
    }
    return ;
}