P3044 [USACO12FEB]搬迁Relocation

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好多多次最短路==，人工全排列了一下

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#include<bits/stdc++.h>
using namespace std;
int ne,head[10010],n,m,a,b,c,k,ans=0x3f3f3f3f,vis[10010],d[10][10010],num[10],flg[10],bol[10010];
struct node{int to,nxt,dis;}eg[100100];
void adde(int u,int v,int c){eg[++ne].nxt=head[u];eg[ne].dis=c;eg[ne].to=v;head[u]=ne;}
void spfa(int x)
{
    memset(vis,0,sizeof(vis));
    queue<int>q;
    q.push(num[x]);d[x][num[x]]=0;vis[num[x]]=1;
    while(!q.empty())
    {
        int u=q.front();vis[u]=0;q.pop();
        for(int i=head[u];i;i=eg[i].nxt)
        {
            int v=eg[i].to;
            if(d[x][v]>d[x][u]+eg[i].dis)
            {d[x][v]=d[x][u]+eg[i].dis;
            if(!vis[v]){q.push(v);vis[v]=1;}}
        }
    }
}
void cl(int zt)
{
    int tag[10];
    memset(tag,0,sizeof(tag));
    for(int i=1;i<=k;i++)
    {tag[i]=zt%10;bol[num[tag[i]]]=1;zt/=10;}
    int tot=0,u=tag[1],v=tag[k];
    for(int i=1;i<k;i++)tot+=d[tag[i]][num[tag[i+1]]];
    int tk=0x3f3f3f3f;
    for(int i=1;i<=n;i++)if(!bol[i])tk=min(d[u][i]+d[v][i],tk);
    ans=min(ans,tot+tk);
    for(int i=1;i<=k;i++){bol[num[tag[i]]]=0;}
}
void dfs(int zt,int nod)
{
    if(nod==k)cl(zt);
    else {
        for(int i=1;i<=k;i++)
        if(!flg[i]){flg[i]=1;dfs(zt*10+i,nod+1);flg[i]=0;
        }
    }
}
int main()
{
    memset(d,0x3f,sizeof(d));
    cin>>n>>m>>k;
    for(int i=1;i<=k;i++)cin>>num[i];
    while(m--){cin>>a>>b>>c;adde(a,b,c);adde(b,a,c);}
    for(int i=1;i<=k;i++)spfa(i);
    dfs(0,0);
    cout<<ans;
}