[模板] Dijkstra单源最短路径

#define maxn 100000
#define maxm 100000
using namespace std;
const int INF=999999999;
struct HeapNode
{
	int d,u;
	bool operator < (const HeapNode& rhs) const
	{
		return d>rhs.d;
	}
};
struct Edge
{
	int from,to,dist;
	Edge(int u,int v,int d):from(u),to(v),dist(d) {}
};
struct Dijkstra
{
	int n,m;
	vector<Edge> edges;
	vector<int> G[maxn];
	bool done[maxn];//是否用过（永久标号） 
	int d[maxn];//s到各个点的距离 （dist） 
	int p[maxn];//最短路上的一条边 （path） 
	
	void init(int n)
	{
		this->n=n;
		for(int i=0;i<n;i++)
		{
			G[i].clear(); 
		}
		edges.clear();
	} 
	
	void AddEdge(int from,int to,int dist)
	{
		edges.push_back(Edge(from,to,dist));
		m=edges.size();
		G[from].push_back(m-1);
	}
	
	void dijkstra(int s)
	{
		priority_queue<HeapNode> Q;
		for(int i=0;i<n;i++)
		{
			d[i]=INF;
		}
		d[s]=0;
		memset(done,0,sizeof(done));
		Q.push((HeapNode){0,s});
		while(!Q.empty())
		{
			HeapNode x=Q.top();
			Q.pop();
			int u=x.u;
			if(done[n])
			{
				continue;
			}
			done[u]=true;
			for(int i=0;i<G[u].size();i++)
			{
				Edge& e=edges[G[u][i]];
				if(d[e.to]>d[u]+e.dist)
				{
					d[e.to]=d[u]+e.dist;
					p[e.to]=G[u][i];
					Q.push((HeapNode){d[e.to],e.to});
				}
			}
		}
	}
};