#include<vector> using namespace std; vector<int> g[2000000]; int n,u[2000000],q,p; int sz[2000000],pa[2000000]; void crset(int a) { sz[a]=1; pa[a]=a; } int getparent(int a) { if(pa[a]==a) return a; pa[a]=getparent(pa[a]); return pa[a]; } void setunion(int a,int b) { a=pa[a]; b=pa[b]; if(a==b) { q++; p+=sz[a]; } if(a>b) { sz[a]+=sz[b]; pa[b]=a; } if(a<b) { sz[b]+=sz[a]; pa[a]=b; } } void dfs(int v) { u[v]=1; for(int j=0;j<g[v].size();j++) { int to=g[v][j]; if(u[to]==0) dfs(to); } } int stug (int x) { int mq=0; for(int i=0;i<n;i++) { if(i==x) continue; int qq=0; for(int j=0;j<g[i].size();j++) { int to= g[i][j]; if(to==x) continue; qq++; } if(qq==3) return 0; if(qq==0) mq+=2; if(qq==1) mq+=1; } for(int i=0;i<n;i++) u[i]=0; u[x]=1; int xq=0; for(int i=0;i<n;i++) { if(u[i]==0) { dfs(i); xq++; } } if(2*xq==mq) return 1; else return 0; } void Init(int N_) { n = N_; } void Link(int A, int B) { g[A].push_back(B); g[B].push_back(A); } int CountCritical() { for(int i=0;i<n;i++) { if(g[i].size()==4) { if(stug(i)) return 1; else return 0; } } for(int i=0;i<n;i++) { if(g[i].size()==3) { p=0; if(stug(i)) p++; for(int j=0;j<g[i].size();j++) { int to=g[i][j]; if(stug(to)) p++; } return p; } } p=0; q=0; for(int i=0;i<n;i++) crset(i); for(int i=0;i<n;i++) { for(int j=0;j<g[i].size();j++) { int to=g[i][j]; if(to>i) setunion(i,to); } } if(q==1) return p; if(q>1) return 0; if(q==0) return n; }

rings.cpp: In function 'void dfs(int)':
rings.cpp:41:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int j=0;j<g[v].size();j++)
                 ~^~~~~~~~~~~~
rings.cpp: In function 'int stug(int)':
rings.cpp:56:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int j=0;j<g[i].size();j++)
                     ~^~~~~~~~~~~~
rings.cpp: In function 'int CountCritical()':
rings.cpp:117:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for(int j=0;j<g[i].size();j++)
                         ~^~~~~~~~~~~~
rings.cpp:132:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int j=0;j<g[i].size();j++)
                     ~^~~~~~~~~~~~
rings.cpp:145:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^