hdu 5876 Sparse Graph icpc大连站网络赛 1009 补图最短路

BFS+链表

代码改自某博客

 #include<stdio.h>
 #include<iostream>
 #include<algorithm>
 #include<math.h>
 #include<string.h>
 #include<string>
 #include<map>
 #include<set>
 #include<vector>
 #include<queue>
 using namespace std;
 const int maxn = 2e5+;
 const int INF  = 0x3f3f3f3f;
 const int A=INF;
 const int B=;
 typedef long long LL;
 int h[maxn],e;
 LL dis[maxn];
 bool vis[maxn];
 int start;

 struct Edge
 {
     int v,nxt,w;
 } E[maxn<<];

 void init()
 {
     e=;
     memset(h,-,sizeof h);
     memset(vis,false,sizeof vis);
 }

 void add(int u,int v,int w)
 {
     E[e].v = v;
     E[e].w = w;
     E[e].nxt = h[u];
     h[u]  = e++;
 }

 struct QNode
 {
     int v,c;
     QNode(int _v,int _c)
     {
         v = _v;
         c=_c;
     }
     bool operator < (const QNode &a) const
     {
         return c>a.c;
     }
 };

 void dijkstra(int n)
 {
     memset(dis,INF,sizeof dis);
     priority_queue<QNode>Q;
     dis[] = ;
     Q.push(QNode(,));
     while(!Q.empty())
     {
         QNode tmp = Q.top();
         Q.pop();
         int u = tmp.v;
         if(vis[u]) continue;
         vis[u] = true;
         for(int i=h[u]; ~i; i=E[i].nxt)
         {
             int v = E[i].v;
             int w = E[i].w;
             if(vis[v]) continue;
             if(dis[u]+w<dis[v])
             {
                 dis[v] = dis[u]+w;
                 Q.push(QNode(v,dis[v]));
             }
         }
     }
 }

 void BFS(int n,LL val)
 {
     set<int>ta,tb;
     queue<int>Q;
     Q.push(start);
     dis[start] = ,dis[n] = INF;
     for(int i=; i<=n; i++){
         if(i==start) continue;
         ta.insert(i);
     }
     while(!Q.empty())
     {
         int u = Q.front();
         Q.pop();
         for(int i=h[u]; ~i; i=E[i].nxt)
         {
             int v = E[i].v;
             if(!ta.count(v)) continue;
             ta.erase(v);
             tb.insert(v);
         }
         for(set<int>::iterator it=ta.begin(); it!=ta.end(); it++)
         {
             Q.push(*it);
             dis[*it] = dis[u] + val;
         }
         ta.swap(tb);
         tb.clear();
     }
 }

 int main()
 {
     int N,M,T;
     int u,v;
     while(scanf("%d",&T)!=EOF)
     {
         while(T--)
         {
             scanf("%d%d",&N,&M);
             init();
             bool flag = false;
             for(int i=; i<M; i++)
             {
                 scanf("%d%d",&u,&v);
                 add(u,v,A);
                 add(v,u,A);

             }
             scanf("%d",&start);
             dijkstra(N);
             BFS(N,B);
             bool first=;
             for(int i=;i<=N;i++)
             {
                 if(i==start) continue;
                 if(first) printf(" ");
                 printf("%d",dis[i]);
                 first=;
             }
             printf("\n");
         }
     }
     return ;
 }

 /*

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 */