## 公园 ![在这里插入图片描述](https://img-blog.csdnimg.cn/direct/320124a5f52745a1ab8892a6ba2022ea.png) ![在这里插入图片描述](https://img-blog.csdnimg.cn/direct/f884491141c44555a82370daa125ae7f.png) ![在这里插入图片描述](https://img-blog.csdnimg.cn/direct/d1b871b9679947b5a97a924ea65cf805.png) ## 图论+dijkstra ![在这里插入图片描述](https://img-blog.csdnimg.cn/direct/8032d4193a874976b61e1016dd58d6d1.png) ```cpp #include using namespace std; typedef long long ll; typedef pair pii; vector v[40005]; //a、b、c分别是小度、度度熊、终点到各个点的最短距离 ll a[40005],b[40005],c[40005],dist[40005],st[40005]; void dij(ll idx,ll e) { memset(st,0,sizeof(st)); memset(dist,0x3f,sizeof(dist)); dist[idx]=0; priority_queue,greater> q; q.push({0,idx}); while(!q.empty()) { pii p=q.top(); q.pop(); ll a=p.first; ll b=p.second; if(st[b]) continue; st[b]=1; for(ll i=0;ia+e) { dist[c]=a+e; q.push({dist[c],c}); } } } } int main() { ll te,fe,s,t,f,n,m; cin>>te>>fe>>s>>t>>f>>n>>m; for(int i=0;i>a>>b; v[a].push_back(b); v[b].push_back(a); } dij(t,te); for(ll i=1;i<=n;i++) a[i]=dist[i]; dij(f,fe); for(ll i=1;i<=n;i++) b[i]=dist[i]; dij(n,fe+te-s); for(ll i=1;i<=n;i++) c[i]=dist[i]; ll res=0x3f3f3f3f; for(ll i=1;i<=n;i++) { if(a[i]>=0x3f3f3f3f||b[i]>=0x3f3f3f3f||c[i]>=0x3f3f3f3f) continue; res=min(res,a[i]+b[i]+c[i]); } if(res>=0x3f3f3f3f) cout<<-1<