#include <cstdio>
#include <vector>
#include <queue>
#include <algorithm>
#include <cstring>
using namespace std;
vector<int> graph[1000005];
int n;
struct disj{
int pa[1000005];
int degcnt[1000005][5];
int repres3[1000005];
int repres4[1000005];
int cnt[1000005];
int size[1000005];
bool trash[1000005];
bool bad[1000005];
bool cycle[1000005];
void init(int n){
for(int i=0; i<=n; i++) pa[i] = i, degcnt[i][0] = 1, size[i] = 1, repres3[i] = repres4[i] = -1;
}
int find(int x){
return pa[x] = (pa[x] == x ? x : find(pa[x]));
}
void uni(int p, int q){
p = find(p); q = find(q);
if(p == q) return;
pa[q] = p; find(q);
for(int i=0; i<5; i++){
degcnt[p][i] += degcnt[q][i];
}
size[p] += size[q];
if(degcnt[p][4] > 1){
trash[p] = 1;
bad[p] = 0;
cycle[p] = 0;
return;
}
else{
repres4[p] = max(repres4[p], repres4[q]);
repres3[p] = max(repres3[p], repres3[q]);
}
if(degcnt[p][3] || degcnt[p][4]){
bad[p] = 1;
cycle[p] = 0;
}
else if(degcnt[p][1] == 0){
cycle[p] = 1;
}
}
}disj;
void Init(int N){
n = N;
disj.init(n);
}
int deg[1000005];
void Link(int A, int B){
graph[A].push_back(B);
graph[B].push_back(A);
deg[A]++, deg[B]++;
int p = disj.find(A);
if(deg[A] <= 4){
disj.degcnt[p][deg[A]-1]--;
disj.degcnt[p][deg[A]]++;
if(deg[A] == 3) disj.repres3[p] = A;
if(deg[A] == 4) disj.repres4[p] = A;
}
p = disj.find(B);
if(deg[B] <= 4){
disj.degcnt[p][deg[B]-1]--;
disj.degcnt[p][deg[B]]++;
if(deg[B] == 3) disj.repres3[p] = B;
if(deg[B] == 4) disj.repres4[p] = B;
}
disj.uni(A,B);
}
bool vis[1000005];
queue<int> q;
bool tvis[1000005];
int solve(int x){
memset(tvis,0,sizeof(tvis));
tvis[x] = 1;
int ret = 1;
for(auto &i : graph[x]){
deg[x]--;
deg[i]--;
}
for(auto &i : graph[x]){
if(tvis[i]) continue;
tvis[i] = 1;
q.push(i);
int foundThree = 0, foundOne = 0, foundTwo = 0;
while(!q.empty()){
int qf = q.front();
q.pop();
if(deg[qf] >= 3) foundThree = 1;
if(deg[qf] == 1) foundOne = 1;
if(deg[qf] == 2) foundTwo = 1;
for(auto &i : graph[qf]){
if(!tvis[i]){
tvis[i] = 1;
q.push(i);
}
}
}
if(foundThree == 1){
ret = 0;
break;
}
if(foundTwo && !foundOne){
ret = 0;
break;
}
}
for(auto &i : graph[x]){
deg[x]++;
deg[i]++;
}
return ret;
}
int CountCritical(){
int ret = 0;
for(int i=0; i<n; i++){
if(solve(i)) ret++;
}
return ret;
memset(vis,0,sizeof(vis));
int ret = 0, pos = -1;
for(int i=0; i<n; i++){
int p = disj.find(i);
if(vis[p]) continue;
vis[p] = 1;
if(disj.trash[p]) return 0;
else if(disj.cycle[p]){
if(~pos) return 0;
pos = p;
ret = disj.size[p];
}
else if(disj.bad[p]){
if(~pos) return 0;
pos = p;
ret = -1;
}
else{
if(pos == -1) ret += disj.size[p];
}
}
if(ret == -1){
if(~disj.repres4[pos]){
ret = 0;
pos = disj.repres4[pos];
return solve(pos);
}
else{
ret = 0;
pos = disj.repres3[pos];
if(solve(pos)) ret++;
for(auto &k : graph[pos]){
if(solve(k)) ret++;
}
}
}
return ret;
}
Compilation message
rings.cpp: In function 'int CountCritical()':
rings.cpp:141:9: error: redeclaration of 'int ret'
int ret = 0, pos = -1;
^~~
rings.cpp:135:9: note: 'int ret' previously declared here
int ret = 0;
^~~
