結果
問題 | No.1553 Lovely City |
ユーザー |
|
提出日時 | 2021-06-19 19:49:29 |
言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 886 ms / 2,000 ms |
コード長 | 13,146 bytes |
コンパイル時間 | 5,634 ms |
コンパイル使用メモリ | 218,960 KB |
最終ジャッジ日時 | 2025-01-22 10:20:59 |
ジャッジサーバーID (参考情報) |
judge5 / judge4 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 2 |
other | AC * 26 |
ソースコード
#include <stdio.h>#include <bits/stdc++.h>// #include <boost/multiprecision/cpp_int.hpp>// using Bint = boost::multiprecision::cpp_int;#define REP(i, n) for(int i = 0;i < n;i++)#define ll long longusing namespace std;typedef pair<int, int> P;typedef pair<ll,ll> LP;const int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};const int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};const int INF = 1000000000;const ll LINF = 1000000000000000000;//1e18const double PI = acos(-1.0);const double EPS = 1e-10;template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }inline constexpr ll ceil_div(const ll a, const ll b) {return (a + b - 1) / b - !!((a + b - 1) % b < 0);}// return ceil(a/b)inline constexpr ll floor_div(const ll a, const ll b) {return a / b - !!(a % b < 0);}// return floor(a/b)/* ----------------------- DEBUG FUNCTION ---------------------------- */#define DUMPOUT cerrvoid dump_function() { DUMPOUT << ' '; }void dump_function(bool a) { DUMPOUT << a; }void dump_function(int a) { DUMPOUT << a; }void dump_function(long long a) { DUMPOUT << a; }void dump_function(char a) { DUMPOUT << a; }void dump_function(string &a) { DUMPOUT << a; }void dump_function(double a) { DUMPOUT << a; }template <class T> void dump_function(const vector<T> &);template <class T, size_t size> void dump_function(const array<T, size> &);template <class T, class L> void dump_function(const pair<T, L> &p);template <class T, size_t size> void dump_function(const T (&)[size]);template <class T> void dump_function(const vector<T> &a) {if(a.empty()) return;dump_function(a[0]);for(auto i = a.begin(); ++i != a.end();) {DUMPOUT << " ";dump_function(*i);}DUMPOUT << endl;}template <class T> void dump_function(const deque<T> &a) {if(a.empty()) return;dump_function(a[0]);for(auto i = a.begin(); ++i != a.end();) {DUMPOUT << " ";dump_function(*i);}}template <class T, size_t size> void dump_function(const array<T, size> &a) {dump_function(a[0]);for(auto i = a.begin(); ++i != a.end();) {DUMPOUT << " ";dump_function(*i);}}template <class T, class L> void dump_function(const pair<T, L> &p) {DUMPOUT << '(';dump_function(p.first);DUMPOUT << ",";dump_function(p.second);DUMPOUT << ')';}template <class T> void dump_function(set<T> &x) {for(auto e : x) dump_function(e), DUMPOUT << " ";DUMPOUT << endl;}template <class T> void dump_function(multiset<T> &x) {for(auto e : x) dump_function(e), DUMPOUT << " ";DUMPOUT << endl;}template <class T, size_t size> void dump_function(const T (&a)[size]) {dump_function(a[0]);for(auto i = a; ++i != end(a);) {DUMPOUT << " ";dump_function(*i);}}template <class T> void dump_function(const T &a) { DUMPOUT << a; }int dump_out() {DUMPOUT << '\n';return 0;}template <class T> int dump_out(const T &t) {dump_function(t);DUMPOUT << '\n';return 0;}template <class Head, class... Tail> int dump_out(const Head &head, const Tail &... tail) {dump_function(head);DUMPOUT << ' ';dump_out(tail...);return 0;}#ifdef DEBUG_#define dump(x)\DUMPOUT << #x << ": ";\dump_function(x);\DUMPOUT << endl;void dumps() {}template <class T> void dumps(const T &t) {dump_function(t);DUMPOUT << " ";}template <class Head, class... Tail> void dumps(const Head &head, const Tail &... tail) {dump_function(head);DUMPOUT << ' ';dump_out(tail...);}#else#define dump(x)template <class... T> void dumps(const T &...) {}#endif/* ----------------------- DEBUG FUNCTION ---------------------------- */template<int MOD> struct Fp {long long val;constexpr Fp(long long v = 0) noexcept : val(v % MOD) {if (val < 0) val += MOD;}constexpr int getmod() const { return MOD; }constexpr Fp operator - () const noexcept {return val ? MOD - val : 0;}constexpr Fp operator + (const Fp& r) const noexcept { return Fp(*this) += r; }constexpr Fp operator - (const Fp& r) const noexcept { return Fp(*this) -= r; }constexpr Fp operator * (const Fp& r) const noexcept { return Fp(*this) *= r; }constexpr Fp operator / (const Fp& r) const noexcept { return Fp(*this) /= r; }constexpr Fp& operator += (const Fp& r) noexcept {val += r.val;if (val >= MOD) val -= MOD;return *this;}constexpr Fp& operator -= (const Fp& r) noexcept {val -= r.val;if (val < 0) val += MOD;return *this;}constexpr Fp& operator *= (const Fp& r) noexcept {val = val * r.val % MOD;return *this;}constexpr Fp& operator /= (const Fp& r) noexcept {long long a = r.val, b = MOD, u = 1, v = 0;while (b) {long long t = a / b;a -= t * b, swap(a, b);u -= t * v, swap(u, v);}val = val * u % MOD;if (val < 0) val += MOD;return *this;}constexpr bool operator == (const Fp& r) const noexcept {return this->val == r.val;}constexpr bool operator != (const Fp& r) const noexcept {return this->val != r.val;}friend constexpr istream& operator >> (istream& is, Fp<MOD>& x) noexcept {is >> x.val;x.val %= MOD;if (x.val < 0) x.val += MOD;return is;}friend constexpr ostream& operator << (ostream& os, const Fp<MOD>& x) noexcept {return os << x.val;}friend constexpr Fp<MOD> modpow(const Fp<MOD>& r, long long n) noexcept {if (n == 0) return 1;auto t = modpow(r, n / 2);t = t * t;if (n & 1) t = t * r;return t;}friend constexpr Fp<MOD> modinv(const Fp<MOD>& r) noexcept {long long a = r.val, b = MOD, u = 1, v = 0;while (b) {long long t = a / b;a -= t * b, swap(a, b);u -= t * v, swap(u, v);}return Fp<MOD>(u);}};template<class T> struct BiCoef {vector<T> fact_, inv_, finv_;constexpr BiCoef() {}constexpr BiCoef(int n) noexcept : fact_(n, 1), inv_(n, 1), finv_(n, 1) {init(n);}constexpr void init(int n) noexcept {fact_.assign(n, 1), inv_.assign(n, 1), finv_.assign(n, 1);int MOD = fact_[0].getmod();for(int i = 2; i < n; i++){fact_[i] = fact_[i-1] * i;inv_[i] = -inv_[MOD%i] * (MOD/i);finv_[i] = finv_[i-1] * inv_[i];}}constexpr T nCr(int n, int k) const noexcept {if (n < k || n < 0 || k < 0) return 0;int MOD = fact_[0].getmod();if(n < MOD) return fact_[n] * finv_[k] * finv_[n-k];// Lucasの定理T ret = 1;while(n || k){int _n = n % MOD, _k = k % MOD;n /= MOD;k /= MOD;ret *= nCr(_n, _k);}return ret;}constexpr T nPr(int n, int k) const noexcept {if (n < k || n < 0 || k < 0) return 0;return fact_[n] * finv_[n-k];}constexpr T nHr(int n, int k) const noexcept {if (n < k || n < 0 || k < 0) return 0;return fact_[n] * finv_[n-k];}constexpr T fact(int n) const noexcept {if (n < 0) return 0;return fact_[n];}constexpr T inv(int n) const noexcept {if (n < 0) return 0;return inv_[n];}constexpr T finv(int n) const noexcept {if (n < 0) return 0;return finv_[n];}};/* ----------------------------- MOD ----------------------------------- */const int MOD = 1000000007;const int MOD2 = 998244353;using mint = Fp<MOD>;BiCoef<mint> bc;// using vec = vector<int>;// using mat = vector<vec>;/* ----------------------------- MOD ----------------------------------- *//* ----------------------- AtCoder Library ---------------------------- */// #include <atcoder/all>// using namespace atcoder;/* ----------------------- AtCoder Library ---------------------------- *///UnionFindstruct UnionFind {vector<int> par;UnionFind(int n) : par(n, -1) { }void init(int n) { par.assign(n, -1); }int root(int x) {if (par[x] < 0) return x;else return par[x] = root(par[x]);}bool issame(int x, int y) {return root(x) == root(y);}bool unite(int x, int y) {x = root(x); y = root(y);if (x == y) return false;if (par[x] > par[y]) swap(x, y); // merge techniquepar[x] += par[y];par[y] = x;return true;}int size(int x) {return -par[root(x)];}};class StronglyConnectedComponents{int nodeNum;int size;public:vector<vector<int>> edge,revEdge;vector<vector<int>> graph;vector<int> label,visited,order;// 帰りがけ順に番号を振っていくvoid dfs(int cur){visited[cur] = 1;for(int next:edge[cur]) if(!visited[next]) dfs(next);order.push_back(cur);}// 通ることが出来た頂点に番号を振っていくvoid revDfs(int cur,int labelId){visited[cur] = 1;label[cur] = labelId;for(int next:revEdge[cur]) if(!visited[next]) revDfs(next,labelId);}StronglyConnectedComponents(const int& nodeNum) :nodeNum(nodeNum), edge(nodeNum), revEdge(nodeNum), label(nodeNum), visited(nodeNum) {}void make_edge(const int from,const int to) {edge[from].push_back(to);revEdge[to].push_back(from);}void solve(void) {for(int i = 0; i < nodeNum; ++i) visited[i] = 0;for(int i = 0; i < nodeNum; ++i) if(!visited[i]) dfs(i);for(int i = 0; i < nodeNum; ++i) visited[i] = 0;reverse(order.begin(),order.end());int labelId = 0;for(int i:order) if(!visited[i]) revDfs(i,labelId++);size = labelId;make_graph();}// 強連結成分で縮約したグラフを作るvoid make_graph(){graph.resize(size);for(int i = 0; i < edge.size(); i++){for(auto to : edge[i]){if(getLabel(i) == getLabel(to)) continue;graph[getLabel(i)].push_back(getLabel(to));}}}vector<vector<int>> topological_sort(void){vector<vector<int>> ret(size);for(int i = 0; i < nodeNum; i++) ret[label[i]].emplace_back(i);return ret;}void print(void) {for(auto labelId:label) cout << labelId << " ";cout << endl;}// vが属している強連結成分のラベル(トポロジカル順序)int getLabel(int v){return label[v];}int getSize(){return size;}};template<typename T>struct Compress {vector<T> v;Compress() {}Compress(vector<T> _v) :v(_v) { build(); }void add(T x) {v.emplace_back(x);}void build() {sort(v.begin(), v.end());v.erase(unique(v.begin(), v.end()), v.end());}void build(vector<T> _v) {v = _v;sort(v.begin(), v.end());v.erase(unique(v.begin(), v.end()), v.end());}int get(T x) {return lower_bound(v.begin(), v.end(), x) - v.begin();}T& operator[](int i) { return v[i]; }int size() {return (int)v.size();}};void solve(){int N, M;cin >> N >> M;UnionFind uf(N);vector<int> U(M), V(M);REP(i,M){cin >> U[i] >> V[i];--U[i], --V[i];uf.unite(U[i], V[i]);}vector<vector<pair<int, int>>> v(N);REP(i,M){int num = uf.root(U[i]);v[num].emplace_back(U[i], V[i]);}vector<pair<int, int>> ans;REP(i,N) if(!v[i].empty()){Compress<int> cmp;for(auto [u, v] : v[i]){cmp.add(u);cmp.add(v);}cmp.build();int sz = cmp.size();StronglyConnectedComponents scc(sz);for(auto [u, v] : v[i]){scc.make_edge(cmp.get(u), cmp.get(v));}scc.solve();auto topo = scc.topological_sort();if(scc.getSize() == sz){REP(i,sz-1) ans.emplace_back(cmp[topo[i].front()], cmp[topo[i+1].front()]);}else{REP(i,sz) ans.emplace_back(cmp[i], cmp[(i+1)%sz]);}}cout << ans.size() << endl;for(auto [u, v] : ans) cout << u+1 << " " << v+1 << endl;}int main(){cin.tie(0);ios::sync_with_stdio(false);solve();// int T; cin >> T; REP(t,T) solve();}