結果
問題 | No.1553 Lovely City |
ユーザー |
![]() |
提出日時 | 2021-06-19 20:18:05 |
言語 | C++17(gcc12) (gcc 12.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 559 ms / 2,000 ms |
コード長 | 7,980 bytes |
コンパイル時間 | 10,367 ms |
コンパイル使用メモリ | 286,376 KB |
最終ジャッジ日時 | 2025-01-22 10:22:24 |
ジャッジサーバーID (参考情報) |
judge1 / 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
#define LOCAL#include <bits/stdc++.h>using namespace std;#pragma region Macrostypedef long long ll;typedef __int128_t i128;typedef unsigned int uint;typedef unsigned long long ull;#define ALL(x) (x).begin(), (x).end()template <typename T> istream& operator>>(istream& is, vector<T>& v) {for (T& x : v) is >> x;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 == (int)v.size() ? "" : " ");}return os;}template <typename T, typename U> ostream& operator<<(ostream& os, const pair<T, U>& p) {os << '(' << p.first << ',' << p.second << ')';return os;}template <typename T, typename U, typename V> ostream& operator<<(ostream& os, const tuple<T, U, V>& t) {os << '(' << get<0>(t) << ',' << get<1>(t) << ',' << get<2>(t) << ')';return os;}template <typename T, typename U, typename V, typename W> ostream& operator<<(ostream& os, const tuple<T, U, V, W>& t) {os << '(' << get<0>(t) << ',' << get<1>(t) << ',' << get<2>(t) << ',' << get<3>(t) << ')';return os;}template <typename T, typename U> ostream& operator<<(ostream& os, const map<T, U>& m) {os << '{';for (auto itr = m.begin(); itr != m.end();) {os << '(' << itr->first << ',' << itr->second << ')';if (++itr != m.end()) os << ',';}os << '}';return os;}template <typename T, typename U> ostream& operator<<(ostream& os, const unordered_map<T, U>& m) {os << '{';for (auto itr = m.begin(); itr != m.end();) {os << '(' << itr->first << ',' << itr->second << ')';if (++itr != m.end()) os << ',';}os << '}';return os;}template <typename T> ostream& operator<<(ostream& os, const set<T>& s) {os << '{';for (auto itr = s.begin(); itr != s.end();) {os << *itr;if (++itr != s.end()) os << ',';}os << '}';return os;}template <typename T> ostream& operator<<(ostream& os, const multiset<T>& s) {os << '{';for (auto itr = s.begin(); itr != s.end();) {os << *itr;if (++itr != s.end()) os << ',';}os << '}';return os;}template <typename T> ostream& operator<<(ostream& os, const unordered_set<T>& s) {os << '{';for (auto itr = s.begin(); itr != s.end();) {os << *itr;if (++itr != s.end()) os << ',';}os << '}';return os;}template <typename T> ostream& operator<<(ostream& os, const deque<T>& v) {for (int i = 0; i < (int)v.size(); i++) {os << v[i] << (i + 1 == (int)v.size() ? "" : " ");}return os;}void debug_out() { cerr << '\n'; }template <class Head, class... Tail> void debug_out(Head&& head, Tail&&... tail) {cerr << head;if (sizeof...(Tail) > 0) cerr << ", ";debug_out(move(tail)...);}#ifdef LOCAL#define debug(...) \cerr << " "; \cerr << #__VA_ARGS__ << " :[" << __LINE__ << ":" << __FUNCTION__ << "]" << '\n'; \cerr << " "; \debug_out(__VA_ARGS__)#else#define debug(...) 42#endiftemplate <typename T> T gcd(T x, T y) { return y != 0 ? gcd(y, x % y) : x; }template <typename T> T lcm(T x, T y) { return x / gcd(x, y) * y; }template <class T1, class T2> inline bool chmin(T1& a, T2 b) {if (a > b) {a = b;return true;}return false;}template <class T1, class T2> inline bool chmax(T1& a, T2 b) {if (a < b) {a = b;return true;}return false;}#pragma endregion/*** @brief UnionFind* @docs docs/datastructure/UnionFind.md*/struct UnionFind {int num;vector<int> par, rank;UnionFind(int n) : num(n), par(n), rank(n, 1) { iota(par.begin(), par.end(), 0); }int root(int x) { return (par[x] == x ? x : par[x] = root(par[x])); }bool merge(int x, int y) {x = root(x);y = root(y);if (x == y) return false;if (rank[x] < rank[y]) swap(x, y);par[y] = x;rank[x] += rank[y];num--;return true;}bool same(int x, int y) { return root(x) == root(y); }int size(int x) { return rank[root(x)]; }int count() { return num; }int operator[](int x) { return root(x); }};/*** @brief Cycle Detection* @docs docs/graph/CycleDetection.md*/template <bool directed> struct CycleDetection {vector<vector<int>> G;vector<int> seen, finished;stack<int> hist;int pos;CycleDetection(int n) : G(n), seen(n, 0), finished(n, 0), pos(-1) {}void add_edge(int u, int v) { G[u].emplace_back(v); }void dfs(int v, int p) {seen[v] = 1;hist.emplace(v);for (int u : G[v]) {if (!directed && u == p) continue;if (finished[u]) continue;if (seen[u] && !finished[u]) {pos = u;return;}dfs(u, v);if (~pos) return;}finished[v] = 1;hist.pop();}vector<int> build() {for (int v = 0; v < (int)G.size(); v++) {if (!seen[v]) dfs(v, -1);if (~pos) break;}vector<int> res;while (!hist.empty()) {int t = hist.top();hist.pop();res.emplace_back(t);if (t == pos) break;}return res;}};/*** @brief Topological Sort* @docs docs/graph/TopologicalSort.md*/struct TopologicalSort {vector<vector<int>> G;vector<int> seen, order;TopologicalSort(int n) : G(n), seen(n) {}void add_edge(int u, int v) { G[u].emplace_back(v); }void dfs(int v) {seen[v] = 1;for (int u : G[v]) {if (!seen[u]) dfs(u);}order.emplace_back(v);}vector<int> build() {for (int i = 0; i < (int)G.size(); i++) {if (!seen[i]) dfs(i);}reverse(order.begin(), order.end());return order;}int operator[](int i) { return order[i]; }};/*** @brief compress*/template <typename T> map<T, int> compress(vector<T>& v) {sort(v.begin(), v.end());v.erase(unique(v.begin(), v.end()), v.end());map<T, int> res;for (int i = 0; i < v.size(); i++) res[v[i]] = i;return res;}const int INF = 1e9;const long long IINF = 1e18;const int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};const char dir[4] = {'D', 'R', 'U', 'L'};const long long MOD = 1000000007;// const long long MOD = 998244353;int main() {cin.tie(0);ios::sync_with_stdio(false);int N, M;cin >> N >> M;vector<int> U(M), V(M);UnionFind UF(N);for (int i = 0; i < M; i++) {cin >> U[i] >> V[i];UF.merge(--U[i], --V[i]);}vector<vector<int>> group(N), es(N);for (int i = 0; i < N; i++) group[UF[i]].emplace_back(i);for (int i = 0; i < M; i++) es[UF[U[i]]].emplace_back(i);vector<pair<int, int>> ans;for (int i = 0; i < N; i++) {if (group[i].empty()) continue;int sz = group[i].size();CycleDetection<true> CD(sz);TopologicalSort TS(sz);map<int, int> mp = compress(group[i]);for (int& e : es[i]) {CD.add_edge(mp[U[e]], mp[V[e]]);TS.add_edge(mp[U[e]], mp[V[e]]);}if (!CD.build().empty()) {for (int j = 0; j < sz; j++) {ans.emplace_back(group[i][j], group[i][(j + 1) % sz]);}} else {TS.build();for (int j = 0; j < sz - 1; j++) ans.emplace_back(group[i][TS[j]], group[i][TS[j + 1]]);}}cout << ans.size() << '\n';for (auto& p : ans) cout << p.first + 1 << ' ' << p.second + 1 << '\n';return 0;}