結果

問題 No.1553 Lovely City
ユーザー bond_cmprog
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
このコードへのチャレンジ
(要ログイン)
ファイルパターン 結果
sample AC * 2
other AC * 26
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

#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 long
using 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;//1e18
const 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 cerr
void 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
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 ---------------------------- */
//UnionFind
struct 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 technique
par[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;
//
void dfs(int cur){
visited[cur] = 1;
for(int next:edge[cur]) if(!visited[next]) dfs(next);
order.push_back(cur);
}
//
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();
}
//
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
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();
}
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