delete pics to save space

1.1841.cpp

@@ -0,0 +1,58 @@
+#include<cstdio>
+#include<queue>
+#include<cstring>
+#include<vector>
+#include<algorithm>
+using namespace std;
+const int maxn=205;
+int n,m;
+vector<int> G[maxn],V[maxn];
+int mark[maxn],tot,vis[maxn],dis[maxn],way[maxn],pre[maxn];
+struct Node { int u,d; };
+inline bool operator<(const Node &a,const Node &b) { return a.d>b.d; }
+void cal(int s)
+{
+	memset(vis,0,sizeof(vis));
+	memset(dis,0x3f,sizeof(dis));
+	memset(way,0,sizeof(way));
+	dis[s]=0;
+	priority_queue<Node> Q;
+	Q.push((Node){s,0});
+	while(Q.size())
+	{
+		int u=Q.top().u,d=Q.top().d; Q.pop();
+		if(vis[u]) continue;
+		vis[u]=true;
+		for(int i=0;i<G[u].size();i++)
+		{
+			int v=G[u][i],w=V[u][i];
+			if(d+w<dis[v]) { dis[v]=d+w; Q.push((Node){v,d+w}); }
+		}
+	}
+	for(int u=1;u<=n;u++) for(int i=0;i<G[u].size();i++)
+	{
+		int v=G[u][i],w=V[u][i];
+		if(dis[u]+w==dis[v]) { way[v]++; pre[v]=u; }
+	}
+	for(int i=1;i<=n;i++) if(way[i]==1&&pre[i]!=s) { mark[pre[i]]=true; tot=1; }
+//	printf("s=%d\n",s);
+//	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]);
+}
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	scanf("%d%d",&n,&m);
+	while(m-->0)
+	{
+		int a,b,c; scanf("%d%d%d",&a,&b,&c);
+		G[a].push_back(b); V[a].push_back(c);
+		G[b].push_back(a); V[b].push_back(c);
+	}
+	for(int i=1;i<=n;i++) cal(i);
+	if(!tot) printf("No important cities.");
+	else for(int i=1;i<=n;i++) if(mark[i]) printf("%d ",i);
+	printf("\n");
+	return 0;
+}