icpc大连站网络赛 1009 补图最短路

Posted 2020-08-08 可是我不配

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代码改自某博客

  1 #include<stdio.h>
  2 #include<iostream>
  3 #include<algorithm>
  4 #include<math.h>
  5 #include<string.h>
  6 #include<string>
  7 #include<map>
  8 #include<set>
  9 #include<vector>
 10 #include<queue>
 11 using namespace std;
 12 const int maxn = 2e5+5;
 13 const int INF  = 0x3f3f3f3f;
 14 const int A=INF;
 15 const int B=1;
 16 typedef long long LL;
 17 int h[maxn],e;
 18 LL dis[maxn];
 19 bool vis[maxn];
 20 int start;
 21 
 22 struct Edge
 23 {
 24     int v,nxt,w;
 25 } E[maxn<<1];
 26 
 27 void init()
 28 {
 29     e=0;
 30     memset(h,-1,sizeof h);
 31     memset(vis,false,sizeof vis);
 32 }
 33 
 34 void add(int u,int v,int w)
 35 {
 36     E[e].v = v;
 37     E[e].w = w;
 38     E[e].nxt = h[u];
 39     h[u]  = e++;
 40 }
 41 
 42 struct QNode
 43 {
 44     int v,c;
 45     QNode(int _v,int _c)
 46     {
 47         v = _v;
 48         c=_c;
 49     }
 50     bool operator < (const QNode &a) const
 51     {
 52         return c>a.c;
 53     }
 54 };
 55 
 56 void dijkstra(int n)
 57 {
 58     memset(dis,INF,sizeof dis);
 59     priority_queue<QNode>Q;
 60     dis[1] = 0;
 61     Q.push(QNode(1,0));
 62     while(!Q.empty())
 63     {
 64         QNode tmp = Q.top();
 65         Q.pop();
 66         int u = tmp.v;
 67         if(vis[u]) continue;
 68         vis[u] = true;
 69         for(int i=h[u]; ~i; i=E[i].nxt)
 70         {
 71             int v = E[i].v;
 72             int w = E[i].w;
 73             if(vis[v]) continue;
 74             if(dis[u]+w<dis[v])
 75             {
 76                 dis[v] = dis[u]+w;
 77                 Q.push(QNode(v,dis[v]));
 78             }
 79         }
 80     }
 81 }
 82 
 83 void BFS(int n,LL val)
 84 {
 85     set<int>ta,tb;
 86     queue<int>Q;
 87     Q.push(start);
 88     dis[start] = 0,dis[n] = INF;
 89     for(int i=1; i<=n; i++){
 90         if(i==start) continue;
 91         ta.insert(i);
 92     }
 93     while(!Q.empty())
 94     {
 95         int u = Q.front();
 96         Q.pop();
 97         for(int i=h[u]; ~i; i=E[i].nxt)
 98         {
 99             int v = E[i].v;
100             if(!ta.count(v)) continue;
101             ta.erase(v);
102             tb.insert(v);
103         }
104         for(set<int>::iterator it=ta.begin(); it!=ta.end(); it++)
105         {
106             Q.push(*it);
107             dis[*it] = dis[u] + val;
108         }
109         ta.swap(tb);
110         tb.clear();
111     }
112 }
113 
114 int main()
115 {
116     int N,M,T;
117     int u,v;
118     while(scanf("%d",&T)!=EOF)
119     {
120         while(T--)
121         {
122             scanf("%d%d",&N,&M);
123             init();
124             bool flag = false;
125             for(int i=0; i<M; i++)
126             {
127                 scanf("%d%d",&u,&v);
128                 add(u,v,A);
129                 add(v,u,A);
130 
131             }
132             scanf("%d",&start);
133             dijkstra(N);
134             BFS(N,B);
135             bool first=0;
136             for(int i=1;i<=N;i++)
137             {
138                 if(i==start) continue;
139                 if(first) printf(" ");
140                 printf("%d",dis[i]);
141                 first=1;
142             }
143             printf("\n");
144         }
145     }
146     return 0;
147 }
148 
149 
150 /*
151 
152 1
153 2 0
154 1
155 
156 */