bzoj3590: [Snoi2013]Quare

#include<iostream>
#include<cstring>
#include<bitset>
#include<vector>
#include<cstdio>
#include<queue>
#define MAXN 15
#define MP(a,b) make_pair(a,b)
#define min(a,b) ((a)<(b)?(a):(b))
#define ma(x) memset(x,0,sizeof(x))
using namespace std;
struct edge
{
	int u,v,w,nxt;
	#define u(x)  ed[x].u
	#define v(x)  ed[x].v
	#define w(x)  ed[x].w
	#define n(x)  ed[x].nxt
}ed[100];
int first[MAXN],num_e=1;
#define f(x) first[x]
int T,n,m;

int f[1<<13];
int g[13][13][1<<13];
int h[2][13][1<<13];

int dfn[MAXN],low[MAXN],cnt;
bool bridge[100],pd;
void tarjan(int x,int edg)
{
	dfn[x]=low[x]=++cnt;
	for(int i=f(x);i;i=n(i))
	if(!dfn[v(i)])
	{
		tarjan(v(i),i),low[x]=min(low[x],low[v(i)]);
		if(low[v(i)]>dfn[x])bridge[i]=bridge[i^1]=1;
	}
	else if(i!=(edg^1))low[x]=min(low[x],dfn[v(i)]);
}
void init()
{
	ma(ed);ma(first);ma(f);ma(g);ma(h);ma(dfn);ma(low);ma(bridge);
	pd=cnt=0;num_e=1;
}
inline void add(int u,int v,int w);
signed main()
{
//	freopen("in.txt","r",stdin);

	scanf("%d",&T);
	while(T--)
	{
		init();
		scanf("%d%d",&n,&m);
		int a,b,c;
		for(int i=1;i<=m;i++)
		{
			scanf("%d%d%d",&a,&b,&c);
			add(a,b,c);add(b,a,c);
		}
		for(int i=1;i<=n;i++)
		if(!dfn[i])tarjan(i,0);	
		for(int i=2;i<=num_e;i++)
		if(bridge[i]){puts("impossible");pd=1;break;}
		if(pd)continue;
		memset(h,0x7f,sizeof(h));
		for(int S=0;S<(1<<n);S++)
			for(int i=1;i<=n;i++)
			if((S|(1<<(i-1)))!=S)		
			{
				for(int j=f(i);j;j=n(j))
				if((S|(1<<(v(j)-1)))==S)
					if(w(j)<h[0][i][S])
					{
						h[1][i][S]=h[0][i][S];
						h[0][i][S]=w(j);
					}
					else if(w(j)<h[1][i][S])h[1][i][S]=w(j);
			}
			else h[0][i][S]=h[1][i][S]=0;
		memset(g,0x7f,sizeof(g));
		for(int S=0;S<(1<<n);S++)
		for(int i=1;i<=n;i++)
			for(int j=1;j<=n;j++)	
				if( (( S|(1<<(i-1)) )==S) && (( S|(1<<(j-1)) )==S) )
					if(i==j && ( S&~(1<<(i-1)) )==0)g[i][j][S]=0;
					else if(i!=j)	
						for(int k=f(j);k;k=n(k))		
						if( ((1<<(v(k)-1))|S)==S )
						g[i][j][S]=min(g[i][j][S],g[i][v(k)][S&~(1<<(j-1))]+w(k));
		memset(f,0x7f,sizeof(f));
		for(int i=0;i<n;i++)f[1<<(i)]=0;
		for(int S=0;S<(1<<n);S++)
		for(int s=0;s<(1<<n);s++)
		if((s|S)==S)
			for(int x=1;x<=n;x++)
			if(((1<<(x-1))|s)!=s && ((1<<(x-1))|S)==S)
			for(int y=1;y<=n;y++)
			if(((1<<(y-1))|s)!=s && ((1<<(y-1))|S)==S)
			{
				if(x!=y)f[S]=min(f[S],1ll*f[s]+g[x][y][S&~s]+h[0][x][s]+h[0][y][s]);
				else    f[S]=min(f[S],1ll*f[s]+g[x][y][S&~s]+h[0][x][s]+h[1][y][s]);
			}
		printf("%d\n",f[(1<<n)-1]);
	}
}
inline void add(int u,int v,int w)
{
	++num_e;
	u(num_e)=u;
	v(num_e)=v;
	w(num_e)=w;
	n(num_e)=f(u);
	f(u)=num_e;
}