This documentation is automatically generated by online-judge-tools/verification-helper
#define PROBLEM "https://yukicoder.me/problems/no/1254"
#include "../../template/template.hpp"
#include "../../graph/others/namori-graph.hpp"
int main() {
int N;
cin >> N;
NamoriGraph< int > g(N);
g.read(N);
g.build();
vector< int > ans;
for(auto &e : g.loop_edges) {
ans.emplace_back(e.idx + 1);
}
sort(begin(ans), end(ans));
cout << ans.size() << "\n";
cout << ans << "\n";
}
#line 1 "test/verify/yukicoder-1254.test.cpp"
#define PROBLEM "https://yukicoder.me/problems/no/1254"
#line 1 "template/template.hpp"
#include<bits/stdc++.h>
using namespace std;
using int64 = long long;
const int mod = 1e9 + 7;
const int64 infll = (1LL << 62) - 1;
const int inf = (1 << 30) - 1;
struct IoSetup {
IoSetup() {
cin.tie(nullptr);
ios::sync_with_stdio(false);
cout << fixed << setprecision(10);
cerr << fixed << setprecision(10);
}
} iosetup;
template< typename T1, typename T2 >
ostream &operator<<(ostream &os, const pair< T1, T2 >& p) {
os << p.first << " " << p.second;
return os;
}
template< typename T1, typename T2 >
istream &operator>>(istream &is, pair< T1, T2 > &p) {
is >> p.first >> p.second;
return is;
}
template< typename T >
ostream &operator<<(ostream &os, const vector< T > &v) {
for(int i = 0; i < (int) v.size(); i++) {
os << v[i] << (i + 1 != v.size() ? " " : "");
}
return os;
}
template< typename T >
istream &operator>>(istream &is, vector< T > &v) {
for(T &in : v) is >> in;
return is;
}
template< typename T1, typename T2 >
inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }
template< typename T1, typename T2 >
inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }
template< typename T = int64 >
vector< T > make_v(size_t a) {
return vector< T >(a);
}
template< typename T, typename... Ts >
auto make_v(size_t a, Ts... ts) {
return vector< decltype(make_v< T >(ts...)) >(a, make_v< T >(ts...));
}
template< typename T, typename V >
typename enable_if< is_class< T >::value == 0 >::type fill_v(T &t, const V &v) {
t = v;
}
template< typename T, typename V >
typename enable_if< is_class< T >::value != 0 >::type fill_v(T &t, const V &v) {
for(auto &e : t) fill_v(e, v);
}
template< typename F >
struct FixPoint : F {
explicit FixPoint(F &&f) : F(forward< F >(f)) {}
template< typename... Args >
decltype(auto) operator()(Args &&... args) const {
return F::operator()(*this, forward< Args >(args)...);
}
};
template< typename F >
inline decltype(auto) MFP(F &&f) {
return FixPoint< F >{forward< F >(f)};
}
#line 4 "test/verify/yukicoder-1254.test.cpp"
#line 2 "graph/others/namori-graph.hpp"
#line 2 "graph/graph-template.hpp"
/**
* @brief Graph Template(グラフテンプレート)
*/
template< typename T = int >
struct Edge {
int from, to;
T cost;
int idx;
Edge() = default;
Edge(int from, int to, T cost = 1, int idx = -1) : from(from), to(to), cost(cost), idx(idx) {}
operator int() const { return to; }
};
template< typename T = int >
struct Graph {
vector< vector< Edge< T > > > g;
int es;
Graph() = default;
explicit Graph(int n) : g(n), es(0) {}
size_t size() const {
return g.size();
}
void add_directed_edge(int from, int to, T cost = 1) {
g[from].emplace_back(from, to, cost, es++);
}
void add_edge(int from, int to, T cost = 1) {
g[from].emplace_back(from, to, cost, es);
g[to].emplace_back(to, from, cost, es++);
}
void read(int M, int padding = -1, bool weighted = false, bool directed = false) {
for(int i = 0; i < M; i++) {
int a, b;
cin >> a >> b;
a += padding;
b += padding;
T c = T(1);
if(weighted) cin >> c;
if(directed) add_directed_edge(a, b, c);
else add_edge(a, b, c);
}
}
inline vector< Edge< T > > &operator[](const int &k) {
return g[k];
}
inline const vector< Edge< T > > &operator[](const int &k) const {
return g[k];
}
};
template< typename T = int >
using Edges = vector< Edge< T > >;
#line 4 "graph/others/namori-graph.hpp"
/**
* @brief Namori Graph
* @docs docs/namori-graph.md
*/
template< typename T = int >
struct NamoriGraph : Graph< T > {
public:
using Graph< T >::Graph;
using Graph< T >::g;
vector< Graph< T > > forest;
Edges< T > loop_edges;
struct Info {
int tree_id, id;
};
Info operator[](const int &k) const {
return (Info) {mark_id[k], id[k]};
}
int inv(int tree_id, int k) {
return iv[tree_id][k];
}
void build() {
int n = (int) g.size();
vector< int > deg(n), used(n);
queue< int > que;
for(int i = 0; i < n; i++) {
deg[i] = (int) g[i].size();
if(deg[i] == 1) {
que.emplace(i);
used[i] = true;
}
}
while(not que.empty()) {
int idx = que.front();
que.pop();
for(auto &e : g[idx]) {
if(used[e.to]) {
continue;
}
--deg[e.to];
if(deg[e.to] == 1) {
que.emplace(e.to);
used[e.to] = true;
}
}
}
int mx = 0;
for(auto &edges : g) {
for(auto &e : edges) mx = max(mx, e.idx);
}
vector< int > edge_used(mx + 1);
vector< int > loop;
for(int v = 0; v < n; v++) {
if(!used[v]) {
for(bool update = true; update;) {
update = false;
loop.emplace_back(v);
for(auto &e : g[v]) {
if(used[e.to] or edge_used[e.idx]) {
continue;
}
edge_used[e.idx] = true;
loop_edges.emplace_back(v, e.to, e.cost, e.idx);
v = e.to;
update = true;
break;
}
}
break;
}
}
loop.pop_back();
mark_id.resize(n);
id.resize(n);
for(int i = 0; i < (int) loop.size(); i++) {
int pre = loop[(i + loop.size() - 1) % loop.size()];
int nxt = loop[(i + 1) % loop.size()];
int sz = 0;
mark_id[loop[i]] = i;
iv.emplace_back();
id[loop[i]] = sz++;
iv.back().emplace_back(loop[i]);
for(auto &e : g[loop[i]]) {
if(e.to != pre and e.to != nxt) {
mark_dfs(e.to, loop[i], i, sz);
}
}
Graph< T > tree(sz);
for(auto &e : g[loop[i]]) {
if(e.to != pre and e.to != nxt) {
tree.g[id[loop[i]]].emplace_back(id[loop[i]], id[e.to], e.cost, e.idx);
tree.g[id[e.to]].emplace_back(id[e.to], id[loop[i]], e.cost, e.idx);
build_dfs(e.to, loop[i], tree);
}
}
forest.emplace_back(tree);
}
}
private:
vector< vector< int > > iv;
vector< int > mark_id, id;
void mark_dfs(int idx, int par, int k, int &l) {
mark_id[idx] = k;
id[idx] = l++;
iv.back().emplace_back(idx);
for(auto &e : g[idx]) {
if(e.to != par) {
mark_dfs(e.to, idx, k, l);
}
}
}
void build_dfs(int idx, int par, Graph< T > &tree) {
for(auto &e : g[idx]) {
if(e.to != par) {
tree.g[id[idx]].emplace_back(id[idx], id[e.to], e.cost, e.idx);
tree.g[id[e.to]].emplace_back(id[e.to], id[idx], e.cost, e.idx);
build_dfs(e.to, idx, tree);
}
}
}
};
#line 6 "test/verify/yukicoder-1254.test.cpp"
int main() {
int N;
cin >> N;
NamoriGraph< int > g(N);
g.read(N);
g.build();
vector< int > ans;
for(auto &e : g.loop_edges) {
ans.emplace_back(e.idx + 1);
}
sort(begin(ans), end(ans));
cout << ans.size() << "\n";
cout << ans << "\n";
}