59 lines
1.4 KiB
C++
59 lines
1.4 KiB
C++
#include<cstdio>
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#include<queue>
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#include<cstring>
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#include<vector>
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#include<algorithm>
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using namespace std;
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const int maxn=205;
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int n,m;
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vector<int> G[maxn],V[maxn];
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int mark[maxn],tot,vis[maxn],dis[maxn],way[maxn],pre[maxn];
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struct Node { int u,d; };
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inline bool operator<(const Node &a,const Node &b) { return a.d>b.d; }
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void cal(int s)
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{
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memset(vis,0,sizeof(vis));
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memset(dis,0x3f,sizeof(dis));
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memset(way,0,sizeof(way));
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dis[s]=0;
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priority_queue<Node> Q;
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Q.push((Node){s,0});
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while(Q.size())
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{
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int u=Q.top().u,d=Q.top().d; Q.pop();
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if(vis[u]) continue;
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vis[u]=true;
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for(int i=0;i<G[u].size();i++)
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{
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int v=G[u][i],w=V[u][i];
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if(d+w<dis[v]) { dis[v]=d+w; Q.push((Node){v,d+w}); }
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}
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}
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for(int u=1;u<=n;u++) for(int i=0;i<G[u].size();i++)
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{
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int v=G[u][i],w=V[u][i];
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if(dis[u]+w==dis[v]) { way[v]++; pre[v]=u; }
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}
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for(int i=1;i<=n;i++) if(way[i]==1&&pre[i]!=s) { mark[pre[i]]=true; tot=1; }
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// printf("s=%d\n",s);
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// for(int i=1;i<=n;i++) printf("dis[%d]=%d way[%d]=%d pre[%d]=%d\n",i,dis[i],i,way[i],i,pre[i]);
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}
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int main()
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{
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#ifdef local
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freopen("pro.in","r",stdin);
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#endif
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scanf("%d%d",&n,&m);
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while(m-->0)
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{
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int a,b,c; scanf("%d%d%d",&a,&b,&c);
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G[a].push_back(b); V[a].push_back(c);
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G[b].push_back(a); V[b].push_back(c);
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}
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for(int i=1;i<=n;i++) cal(i);
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if(!tot) printf("No important cities.");
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else for(int i=1;i<=n;i++) if(mark[i]) printf("%d ",i);
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printf("\n");
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return 0;
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}
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