This documentation is automatically generated by online-judge-tools/verification-helper
View the Project on GitHub beet-aizu/library
// verification-helper: PROBLEM https://judge.yosupo.jp/problem/maximum_independent_set #include<bits/stdc++.h> using namespace std; #define call_from_test #include "../../graph/independentset.cpp" #undef call_from_test signed main(){ cin.tie(0); ios::sync_with_stdio(0); int n,m; cin>>n>>m; IndependentSet G(n); for(int i=0;i<m;i++){ int u,v; cin>>u>>v; G.add_edge(u,v); } int X=G.build(); cout<<X<<endl; for(int i=0;i<X;i++){ if(i) cout<<" "; cout<<G.ans[i]; } cout<<endl; return 0; }
#line 1 "test/yosupo/maximum_independent_set.test.cpp" // verification-helper: PROBLEM https://judge.yosupo.jp/problem/maximum_independent_set #include<bits/stdc++.h> using namespace std; #define call_from_test #line 1 "graph/independentset.cpp" #line 3 "graph/independentset.cpp" using namespace std; #endif //BEGIN CUT HERE struct IndependentSet{ int n; vector<int> deg,used,dead,pre,ans; vector<vector<int> > G; IndependentSet(int n): n(n),deg(n),used(n,0),dead(n,0),G(n){} void add_edge(int u,int v){ G[u].emplace_back(v); G[v].emplace_back(u); } int res,cnt,alive; void dfs(){ if(cnt+alive<=res) return; int v=-1; for(int i=0;i<n;i++){ if(used[i] or dead[i]) continue; if(deg[i]<=1){ v=i; break; } if(v<0 or deg[v]<deg[i]) v=i; } if(v<0) return; if(deg[v]!=1){ dead[v]=1; alive--; for(int u:G[v]) deg[u]--; dfs(); dead[v]=0; alive++; for(int u:G[v]) deg[u]++; } { used[v]=1; alive--; for(int u:G[v]) if(0==dead[u]++) alive-=!used[u]; cnt++; if(res<cnt) pre=used; res=max(res,cnt); dfs(); used[v]=0; alive++; for(int u:G[v]) if(--dead[u]==0) alive+=!used[u]; cnt--; } } int build(){ for(int i=0;i<n;i++) deg[i]=G[i].size(); res=0,cnt=0,alive=n; dfs(); for(int i=0;i<n;i++) if(pre[i]) ans.emplace_back(i); return res; } }; //END CUT HERE #ifndef call_from_test //INSERT ABOVE HERE signed main(){ return 0; } #endif #line 8 "test/yosupo/maximum_independent_set.test.cpp" #undef call_from_test signed main(){ cin.tie(0); ios::sync_with_stdio(0); int n,m; cin>>n>>m; IndependentSet G(n); for(int i=0;i<m;i++){ int u,v; cin>>u>>v; G.add_edge(u,v); } int X=G.build(); cout<<X<<endl; for(int i=0;i<X;i++){ if(i) cout<<" "; cout<<G.ans[i]; } cout<<endl; return 0; }