poj 1511 优先队列优化dijkstra *

题意：两遍最短路

链接：点我

注意结果用long long

 #include<cstdio>
 #include<iostream>
 #include<algorithm>
 #include<cstring>
 #include<cmath>
 #include<queue>
 #include<map>
 using namespace std;
 #define MOD 1000000007
 #define pb(a) push_back(a)
 const int INF=0x3f3f3f3f;
 const double eps=1e-;
 typedef long long ll;
 #define cl(a) memset(a,0,sizeof(a))
 #define ts printf("*****\n");
 const int MAXN=;
 int p[MAXN],q[MAXN],w[MAXN];
 int n,m,tt,cnt;
 /*
 * 使用优先队列优化Dijkstra算法
 * 复杂度O(ElogE)
 * 注意对vector<Edge>E[MAXN]进行初始化后加边
 */
 struct qnode
 {
 int v;
 int c;
 qnode(int _v=,int _c=):v(_v),c(_c){}
 bool operator <(const qnode &r)const
 {
 return c>r.c;
 }
 };
 struct Edge
 {
 int v,cost;
 Edge(int _v=,int _cost=):v(_v),cost(_cost){}
 };
 vector<Edge>E[MAXN];
 bool vis[MAXN];
 int dist[MAXN];
 void Dijkstra(int n,int start)//点的编号从1开始
 {
 memset(vis,false,sizeof(vis));
 for(int i=;i<=n;i++)dist[i]=INF;
 priority_queue<qnode>que;
 while(!que.empty())que.pop();
 dist[start]=;
 que.push(qnode(start,));
 qnode tmp;
 while(!que.empty())
 {
 tmp=que.top();
 que.pop();
 int u=tmp.v;
 if(vis[u])continue;
 vis[u]=true;
 for(int i=;i<E[u].size();i++)
 {
 int v=E[tmp.v][i].v;
 int cost=E[u][i].cost;
 if(!vis[v]&&dist[v]>dist[u]+cost)
 {
 dist[v]=dist[u]+cost;
 que.push(qnode(v,dist[v]));
 }
 }
 }
 }
 void addedge(int u,int v,int w)
 {
 E[u].push_back(Edge(v,w));
 }
 int main()
 {
     int i,j,k;
     #ifndef ONLINE_JUDGE
     freopen("1.in","r",stdin);
     #endif
     scanf("%d",&tt);
     while(tt--)
     {
         scanf("%d%d",&n,&m);
         for(i=;i<=n;i++)    E[i].clear();
         for(i=;i<m;i++)
         {
             scanf("%d%d%d",&p[i],&q[i],&w[i]);
             addedge(p[i],q[i],w[i]);
         }
         Dijkstra(n,);
         ll sum=;
         for(i=;i<=n;i++)
         {
             sum+=dist[i];
         }
         for(i=;i<=n;i++)    E[i].clear();
         for(i=;i<m;i++)    addedge(q[i],p[i],w[i]);
         Dijkstra(n,);
         for(i=;i<=n;i++)
         {
             sum+=dist[i];
         }
         printf("%I64d\n",sum);
     }
 }