Tarjan求强连通(缩点)

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#include<iostream>#include<cstdio>#include<vector>#include<stack> #include<cstring>#include<algorithm>using namespace std;const int maxn=10000+10;bool vis[maxn];int ID[maxn];    //点的颜色编号 int index,ncolor;      vector<int> dfn(maxn),low(maxn),st;vector<vector<int> > color(maxn); //同一种颜色的点 vector<vector<int> > G(maxn);  void Tarjan(int u){dfn[u]=low[u]=++index;vis[u]=true;st.push_back(u);for(int i=0;i<G[u].size();i++){int v=G[u][i];if(!vis[v]){Tarjan(v);low[u]=min(low[u],low[v]);}else if(find(st.begin(),st.end(),v)!=st.end()) //in stacklow[u]=min(low[u],dfn[v]);}if(dfn[u]==low[u]){int v; ncolor++;do{v=st.back(); st.pop_back();color[ncolor].push_back(v);ID[v]=ncolor;}while(v!=u);}}int getGraph(int n){index=ncolor=0;for(int i=1;i<=n;i++)if(!vis[i]) Tarjan(i);}int main(){int n,m;cin>>n>>m;while(m--){int u,v;cin>>u>>v;G[u].push_back(v);}getGraph(n);return 0;}

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