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Verify/LC_scc.test.cpp

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Last update: 2025-04-17 22:07:07+09:00
Problem: https://judge.yosupo.jp/problem/scc

Depends on

Code

#define PROBLEM "https://judge.yosupo.jp/problem/scc"

#include "Template/template.hpp"

#include "Graph/scc.hpp"


int main(){
    int n,m;
    cin>>n>>m;
    SCC scc(n);
    rep(i,0,m){
        int x,y;
        cin>>x>>y;
        scc.add_edge(x,y);
    }
    scc.run();
    vector g(scc.m,vector<int>());
    rep(i,0,n)g[scc.id[i]].push_back(i);
    cout<<g.size()<<'\n';
    rep(i,0,g.size()){
        cout<<g[i].size()<<' ';
        rep(j,0,g[i].size())cout<<g[i][j]<<(j==(int)g[i].size()-1?'\n':' ');
    }
    return 0;
}

#line 1 "Verify/LC_scc.test.cpp"
#define PROBLEM "https://judge.yosupo.jp/problem/scc"

#line 1 "Template/template.hpp"
#include <bits/stdc++.h>

using namespace std;

#define rep(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define rrep(i, a, b) for (int i = (int)(b)-1; i >= (int)(a); i--)
#define ALL(v) (v).begin(), (v).end()
#define UNIQUE(v) sort(ALL(v)), (v).erase(unique(ALL(v)), (v).end())
#define SZ(v) (int)v.size()
#define MIN(v) *min_element(ALL(v))
#define MAX(v) *max_element(ALL(v))
#define LB(v, x) int(lower_bound(ALL(v), (x)) - (v).begin())
#define UB(v, x) int(upper_bound(ALL(v), (x)) - (v).begin())

using uint = unsigned int;
using ll = long long int;
using ull = unsigned long long;
using i128 = __int128_t;
using u128 = __uint128_t;
const int inf = 0x3fffffff;
const ll INF = 0x1fffffffffffffff;

template <typename T, typename S = T> S SUM(const vector<T> &a) {
    return accumulate(ALL(a), S(0));
}
template <typename S, typename T = S> S POW(S a, T b) {
    S ret = 1, base = a;
    for (;;) {
        if (b & 1)
            ret *= base;
        b >>= 1;
        if (b == 0)
            break;
        base *= base;
    }
    return ret;
}
template <typename T> inline bool chmax(T &a, T b) {
    if (a < b) {
        a = b;
        return 1;
    }
    return 0;
}
template <typename T> inline bool chmin(T &a, T b) {
    if (a > b) {
        a = b;
        return 1;
    }
    return 0;
}
template <typename T, typename U> T ceil(T x, U y) {
    assert(y != 0);
    if (y < 0)
        x = -x, y = -y;
    return (x > 0 ? (x + y - 1) / y : x / y);
}
template <typename T, typename U> T floor(T x, U y) {
    assert(y != 0);
    if (y < 0)
        x = -x, y = -y;
    return (x > 0 ? x / y : (x - y + 1) / y);
}
template <typename T> int popcnt(T x) {
    return __builtin_popcountll(x);
}
template <typename T> int topbit(T x) {
    return (x == 0 ? -1 : 63 - __builtin_clzll(x));
}
template <typename T> int lowbit(T x) {
    return (x == 0 ? -1 : __builtin_ctzll(x));
}

template <class T, class U>
ostream &operator<<(ostream &os, const pair<T, U> &p) {
    os << "P(" << p.first << ", " << p.second << ")";
    return os;
}
template <typename T> ostream &operator<<(ostream &os, const vector<T> &vec) {
    os << "{";
    for (int i = 0; i < vec.size(); i++) {
        os << vec[i] << (i + 1 == vec.size() ? "" : ", ");
    }
    os << "}";
    return os;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, const map<T, U> &map_var) {
    os << "{";
    for (auto itr = map_var.begin(); itr != map_var.end(); itr++) {
        os << "(" << itr->first << ", " << itr->second << ")";
        itr++;
        if (itr != map_var.end())
            os << ", ";
        itr--;
    }
    os << "}";
    return os;
}
template <typename T> ostream &operator<<(ostream &os, const set<T> &set_var) {
    os << "{";
    for (auto itr = set_var.begin(); itr != set_var.end(); itr++) {
        os << *itr;
        ++itr;
        if (itr != set_var.end())
            os << ", ";
        itr--;
    }
    os << "}";
    return os;
}
#ifdef LOCAL
#define debug 1
#define show(...) _show(0, #__VA_ARGS__, __VA_ARGS__)
#else
#define debug 0
#define show(...) true
#endif
template <typename T> void _show(int i, T name) {
    cerr << '\n';
}
template <typename T1, typename T2, typename... T3>
void _show(int i, const T1 &a, const T2 &b, const T3 &...c) {
    for (; a[i] != ',' && a[i] != '\0'; i++)
        cerr << a[i];
    cerr << ":" << b << " ";
    _show(i + 1, a, c...);
}
#line 2 "Graph/scc.hpp"

struct SCC{
    int n,m,cur;
    vector<vector<int>> g;
    vector<int> low,ord,id;
    SCC(int _n=0):n(_n),m(0),cur(0),g(_n),low(_n),ord(_n,-1),id(_n){}
    void resize(int _n){
        n=_n;
        g.resize(n);
        low.resize(n);
        ord.resize(n,-1);
        id.resize(n);
    }
    void add_edge(int u,int v){g[u].emplace_back(v);}
    void dfs(int v,vector<int>& used){
        ord[v]=low[v]=cur++;
        used.emplace_back(v);
        for(auto& nxt:g[v]){
            if(ord[nxt]==-1){
                dfs(nxt,used); chmin(low[v],low[nxt]);
            }
            else{
                chmin(low[v],ord[nxt]);
            }
        }
        if(ord[v]==low[v]){
            while(1){
                int add=used.back(); used.pop_back();
                ord[add]=n; id[add]=m;
                if(v==add)break;
            }
            m++;
        }
    }
    void run(){
        vector<int> used;
        rep(v,0,n)if(ord[v]==-1)dfs(v,used);
        for(auto& x:id)x=m-1-x;
    }
};

/**
 * @brief Strongly Connected Components
 */
#line 5 "Verify/LC_scc.test.cpp"

int main(){
    int n,m;
    cin>>n>>m;
    SCC scc(n);
    rep(i,0,m){
        int x,y;
        cin>>x>>y;
        scc.add_edge(x,y);
    }
    scc.run();
    vector g(scc.m,vector<int>());
    rep(i,0,n)g[scc.id[i]].push_back(i);
    cout<<g.size()<<'\n';
    rep(i,0,g.size()){
        cout<<g[i].size()<<' ';
        rep(j,0,g[i].size())cout<<g[i][j]<<(j==(int)g[i].size()-1?'\n':' ');
    }
    return 0;
}