#include<bits/stdc++.h>
using namespace std;
const int maxn = 1e6 + 5;
int n;
vector<int> way[maxn];
vector<int> deg[10];
int cut[maxn];
int sz, cy, vis[maxn];
stack<int> st;
int ok[maxn];
void Init(int _n) {
n = _n;
}
void cycle(int u, int last, int ban) {
if(vis[u]) {
while(!st.empty()) {
int v = st.top(); st.pop();
sz++;
if(v==u) break;
}
cy++;
return ;
}
vis[u] = 1; st.push(u);
for(auto v : way[u]) {
if(v!=ban && v!=last && vis[v]<2) {
cycle(v,u,ban);
}
}
vis[u] = 2;
if(!st.empty()) st.pop();
}
int check(int u) {
memset(cut,0,sizeof(cut));
for(auto v : way[u]) cut[v]++;
for(int i=1;i<=n;i++) if(i!=u && way[i].size()-cut[i]>2) return 0;
sz = cy = 0; memset(vis,0,sizeof(vis));
for(int i=1;i<=n;i++) if(i!=u && !vis[i]) cycle(i,0,u);
return cy==0;
}
int CountCritical() {
for(int i=0;i<=4;i++) deg[i].clear();
for(int x=1;x<=n;x++) deg[min(4,(int)way[x].size())].push_back(x);
if(deg[4].size()) {
memset(ok,0,sizeof(ok));
if(deg[4].size()<=1) {
for(auto u : deg[4]) if(check(u)) ok[u] = 1;
}
int res = 0;
for(int x=1;x<=n;x++) res += ok[x];
return ok.size();
}
if(deg[3].size()) {
memset(ok,0,sizeof(ok));
if(deg[3].size()<=3) {
for(auto u : deg[3]) {
if(check(u)) ok[u] = 1;
for(auto v : way[u]) if(check(v)) ok[v] = 1;
}
}
int res = 0;
for(int x=1;x<=n;x++) res += ok[x];
return res;
}
sz = cy = 0; memset(vis,0,sizeof(vis));
for(int i=1;i<=n;i++) if(!vis[i]) cycle(i,0,0);
if(cy==0) return n;
else if(cy==1) return sz;
else return 0;
}
void Link(int x, int y) {
x++; y++;
way[x].push_back(y); way[y].push_back(x);
}
Compilation message
rings.cpp: In function 'int CountCritical()':
rings.cpp:57:19: error: request for member 'size' in 'ok', which is of non-class type 'int [1000005]'
return ok.size();
^~~~
