#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename U> using ordered_map = tree<T, U, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long ll;
typedef long double ld;
typedef double db;
typedef string str;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<pii> vpii;
typedef vector<pll> vpll;
typedef vector<str> vstr;
#define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
#define FORD(i,j,k,in) for(int i=(j); i >=(k);i-=in)
#define REP(i,b) FOR(i,0,b,1)
#define REPD(i,b) FORD(i,b,0,1)
#define pb push_back
#define mp make_pair
#define ff first
#define ss second
#define all(x) begin(x), end(x)
#define rsz resize
const double EPS = 1e-9;
const int MOD = 1e9+7; // 998244353;
const ll INFF = 1e18;
const int INF = 1e9;
const ld PI = acos((ld)-1);
const vi dy = {1, 0, -1, 0, -1, 1, 1, -1};
const vi dx = {0, 1, 0, -1, -1, 1, -1, 1};
#ifdef DEBUG
#define DBG if(1)
#else
#define DBG if(0)
#endif
#define dbg(x) cout << "(" << #x << " : " << x << ")" << endl;
// ostreams
template <class T, class U>
ostream& operator<<(ostream& out, const pair<T, U> &par) {out << "[" << par.first << ";" << par.second << "]"; return out;}
template <class T>
ostream& operator<<(ostream& out, const set<T> &cont) { out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template <class T, class U>
ostream& operator<<(ostream& out, const map<T, U> &cont) {out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template<class T>
ostream& operator<<(ostream& out, const vector<T> &v){ out << "["; REP(i, v.size()) out << v[i] << ", "; out << "]"; return out;}
// istreams
template<class T>
istream& operator>>(istream& in, vector<T> &v){ for(auto &x : v) in >> x; return in; }
template<class T, class U>
istream& operator>>(istream& in, pair<T, U> &p){ in >> p.ff >> p.ss; return in; }
//searches
template<typename T, typename U>
T bsl(T lo, T hi, U f){ hi++; T mid; while(lo < hi){ mid = (lo + hi)/2; f(mid) ? hi = mid : lo = mid+1; } return lo; }
template<typename U>
double bsld(double lo, double hi, U f, double p = 1e-9){ int r = 3 + (int)log2((hi - lo)/p); double mid; while(r--){ mid = (lo + hi)/2; f(mid) ? hi = mid : lo = mid; } return (lo + hi)/2; }
template<typename T, typename U>
T bsh(T lo, T hi, U f){ lo--; T mid; while(lo < hi){ mid = (lo + hi + 1)/2; f(mid) ? lo = mid : hi = mid-1; } return lo; }
template<typename U>
double bshd(double lo, double hi, U f, double p = 1e-9){ int r = 3+(int)log2((hi - lo)/p); double mid; while(r--){ mid = (lo + hi)/2; f(mid) ? lo = mid : hi = mid; } return (lo + hi)/2; }
// some more utility functions
template<typename T>
pair<T, int> get_min(vector<T> &v){ typename vector<T> :: iterator it = min_element(v.begin(), v.end()); return mp(*it, it - v.begin());}
template<typename T>
pair<T, int> get_max(vector<T> &v){ typename vector<T> :: iterator it = max_element(v.begin(), v.end()); return mp(*it, it - v.begin());}
template<typename T> bool ckmin(T& a, const T& b){return b < a ? a = b , true : false;}
template<typename T> bool ckmax(T& a, const T& b){return b > a ? a = b, true : false;}
template<typename T>
struct edge{
int src;
int dest;
T cost;
};
template<typename T>
class graph{
public:
vector<edge<T>> edges;
vector<vector<int>> adj;
int n;
graph(){};
graph(int _n){
n = _n;
adj.resize(n);
}
};
template<typename T>
class undigraph : public graph<T>{
public:
using graph<T>::edges;
using graph<T>::adj;
using graph<T>::n;
undigraph() : graph<T>(){};
undigraph(int _n) : graph<T>(_n){};
int add_edge(int src, int dest, T cost = 1){
int id = edges.size();
edges.push_back({src, dest, cost});
adj[src].push_back(id);
adj[dest].push_back(id);
return id;
}
};
struct bfs{
vi par;
vi dist;
undigraph<int> g;
go(int s, int forbidden){
par.rsz(g.n, -1);
dist.rsz(g.n, -1);
fill(all(par), -1); fill(all(dist), -1);
queue<int> q;
dist[s] = 0;
dist[forbidden] = 0;
q.push(s);
while(!q.empty()){
int v = q.front();
q.pop();
for(int id : g.adj[v]){
auto e = g.edges[id];
int other = e.src ^ e.dest ^ v;
if(dist[other] == -1 && other != forbidden){
dist[other] = dist[v]+1;
par[other] = v;
q.push(other);
}
}
}
}
vi get_path(int source, int dest, int forbidden){
go(source, forbidden);
vi path;
while(dest != source){
path.pb(dest);
dest = par[dest];
}
path.pb(source);
reverse(all(path));
return path;
}
};
struct AcAutomaton{
int n,r;
undigraph<int> g;
vector<vector<bool>> adjmat;
void read_in(){
cin >> n >> r;
adjmat.rsz(n, vector<bool>(n, 0));
g = undigraph<int>(n);
REP(i, r){
int a, b; cin >> a >> b;
a--; b--;
g.add_edge(a, b);
adjmat[a][b] = true;
adjmat[b][a] = true;
}
}
void solve(){
bfs spath;
spath.g = g;
REP(i, n){
REP(j, g.adj[i].size()){
FOR(k, j+1, g.adj[i].size(), 1){
edge<int> e1 = g.edges[g.adj[i][j]];
edge<int> e2 = g.edges[g.adj[i][k]];
int o1 = e1.src ^ e1.dest ^ i;
int o2 = e2.src ^ e2.dest ^ i;
if(adjmat[o1][o2]) continue;
//cout << "(" << o1 << " " << o2 << " " << i << ")" << endl;
vi cycle = spath.get_path(o1, o2, i);
/* dbg(cycle); */
/* dbg(spath.par); */
cycle.insert(cycle.begin(), i);
//dbg(cycle);
bool can = true;
REP(v, cycle.size()){
if(cycle[v] == o1 || cycle[v] == o2 || cycle[v] == i) continue;
if(v == 2 || v == cycle.size()-2){
if(adjmat[cycle[v]][i]) can = false;
}
else{
if(adjmat[cycle[v]][i]) can = false;
if(adjmat[cycle[v]][o1]) can = false;
if(adjmat[cycle[v]][o2]) can = false;
}
}
if(can){
REP(i, cycle.size()) cout << cycle[i]+1 << (i == cycle.size()-1 ? "\n" : " ");
return;
}
}
}
}
cout << "no" << endl;
}
};
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL); cout.tie(NULL);
int tcase = 1;
while(tcase--){
AcAutomaton solver;
solver.read_in();
solver.solve();
}
return 0;
}
Compilation message
indcyc.cpp:123:28: error: ISO C++ forbids declaration of 'go' with no type [-fpermissive]
123 | go(int s, int forbidden){
| ^
indcyc.cpp: In member function 'int bfs::go(int, int)':
indcyc.cpp:144:5: warning: no return statement in function returning non-void [-Wreturn-type]
144 | }
| ^
indcyc.cpp: In member function 'void AcAutomaton::solve()':
indcyc.cpp:26:40: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
26 | #define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
| ^
indcyc.cpp:28:18: note: in expansion of macro 'FOR'
28 | #define REP(i,b) FOR(i,0,b,1)
| ^~~
indcyc.cpp:177:13: note: in expansion of macro 'REP'
177 | REP(j, g.adj[i].size()){
| ^~~
indcyc.cpp:26:40: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
26 | #define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
| ^
indcyc.cpp:178:17: note: in expansion of macro 'FOR'
178 | FOR(k, j+1, g.adj[i].size(), 1){
| ^~~
indcyc.cpp:26:40: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
26 | #define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
| ^
indcyc.cpp:28:18: note: in expansion of macro 'FOR'
28 | #define REP(i,b) FOR(i,0,b,1)
| ^~~
indcyc.cpp:191:21: note: in expansion of macro 'REP'
191 | REP(v, cycle.size()){
| ^~~
indcyc.cpp:193:40: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
193 | if(v == 2 || v == cycle.size()-2){
| ~~^~~~~~~~~~~~~~~~~
indcyc.cpp:26:40: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
26 | #define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
| ^
indcyc.cpp:28:18: note: in expansion of macro 'FOR'
28 | #define REP(i,b) FOR(i,0,b,1)
| ^~~
indcyc.cpp:203:25: note: in expansion of macro 'REP'
203 | REP(i, cycle.size()) cout << cycle[i]+1 << (i == cycle.size()-1 ? "\n" : " ");
| ^~~
indcyc.cpp:203:71: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
203 | REP(i, cycle.size()) cout << cycle[i]+1 << (i == cycle.size()-1 ? "\n" : " ");
| ~~^~~~~~~~~~~~~~~~~
