#include <cstdio> #include <iostream> #include <algorithm> #include <string> #include <vector> using namespace std; typedef vector<int> VI; typedef long long LL; /* PA-2015 R5 */ /* Korzystałem z kodu zaczęrpniętego z książki Piotr Stańczyka "Algorytmika Praktyczna" - topo sort */ #define FOR(x, b, e) for(int x = b; x <= (e); ++x) #define FORD(x, b, e) for(int x = b; x >= (e); --x) #define REP(x, n) for(int x = 0; x < (n); ++x) #define VAR(v, n) __typeof(n) v = (n) #define ALL(c) (c).begin(), (c).end() #define SIZE(x) ((int)(x).size()) #define FOREACH(i, c) for(VAR(i, (c).begin()); i != (c).end(); ++i) #define PB push_back #define ST first #define ND second template<class V, class E> struct Graph { struct Ed : E { int v; Ed(E p, int w) : E(p), v(w) {} }; struct Ve : V,vector<Ed> {}; vector<Ve> g; Graph(int n=0) : g(n) {} void EdgeD(int b, int e, E d = E()) {g[b].PB(Ed(d,e));} int topo; void TopoDfs(int v){ if (!g[v].t) { g[v].t=1; FOREACH(it,g[v]) { TopoDfs(it->v); } g[v].t=--topo; } } void TopoSort(){ FOREACH(it,g) it->t=0; topo=SIZE(g); FORD(x,topo-1,0) TopoDfs(x); } VI TopoSortV(){ VI res(SIZE(g)); TopoSort(); REP(x,SIZE(g)) res[g[x].t] = x; return res; } }; struct Ve {}; struct Vs { int t; }; int main() { int n, m, b, e; cin >> n >> m; Graph<Vs, Ve> g(n); REP(x,m) { cin >> b >> e; g.EdgeD(b - 1, e - 1); } VI res = g.TopoSortV(); vector<int> inter; bool joined = false; bool cycle_found = false; FOREACH(it, g.g) FOREACH(it2, *it) if (it->t >= g.g[it2->v].t) { cycle_found = true; // cout<< it - g.g.begin() + 1 << " " << it2->v +1 << endl; int from = it - g.g.begin(); int to = it2->v; int topos = g.g[to].t; int frompos = g.g[from].t; // cout << topos << " " << frompos << endl; vector<int> out (res.begin() + topos, res.begin() + frompos + 1); std::sort(out.begin(), out.end()); if(!joined) { inter.insert(inter.begin(), out.begin(), out.end()); joined = true; } else { vector<int> tmp(inter.begin(), inter.end()); inter.clear(); std::set_intersection(out.begin(), out.end(), tmp.begin(), tmp.end(), std::back_inserter(inter)); } } if(!cycle_found) { cout << "NIE\n"; } else { cout << inter.size() << endl; if(inter.size()) { FOREACH(it, inter) cout << *it + 1<< " "; cout <<endl; } } return 0; }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 | #include <cstdio> #include <iostream> #include <algorithm> #include <string> #include <vector> using namespace std; typedef vector<int> VI; typedef long long LL; /* PA-2015 R5 */ /* Korzystałem z kodu zaczęrpniętego z książki Piotr Stańczyka "Algorytmika Praktyczna" - topo sort */ #define FOR(x, b, e) for(int x = b; x <= (e); ++x) #define FORD(x, b, e) for(int x = b; x >= (e); --x) #define REP(x, n) for(int x = 0; x < (n); ++x) #define VAR(v, n) __typeof(n) v = (n) #define ALL(c) (c).begin(), (c).end() #define SIZE(x) ((int)(x).size()) #define FOREACH(i, c) for(VAR(i, (c).begin()); i != (c).end(); ++i) #define PB push_back #define ST first #define ND second template<class V, class E> struct Graph { struct Ed : E { int v; Ed(E p, int w) : E(p), v(w) {} }; struct Ve : V,vector<Ed> {}; vector<Ve> g; Graph(int n=0) : g(n) {} void EdgeD(int b, int e, E d = E()) {g[b].PB(Ed(d,e));} int topo; void TopoDfs(int v){ if (!g[v].t) { g[v].t=1; FOREACH(it,g[v]) { TopoDfs(it->v); } g[v].t=--topo; } } void TopoSort(){ FOREACH(it,g) it->t=0; topo=SIZE(g); FORD(x,topo-1,0) TopoDfs(x); } VI TopoSortV(){ VI res(SIZE(g)); TopoSort(); REP(x,SIZE(g)) res[g[x].t] = x; return res; } }; struct Ve {}; struct Vs { int t; }; int main() { int n, m, b, e; cin >> n >> m; Graph<Vs, Ve> g(n); REP(x,m) { cin >> b >> e; g.EdgeD(b - 1, e - 1); } VI res = g.TopoSortV(); vector<int> inter; bool joined = false; bool cycle_found = false; FOREACH(it, g.g) FOREACH(it2, *it) if (it->t >= g.g[it2->v].t) { cycle_found = true; // cout<< it - g.g.begin() + 1 << " " << it2->v +1 << endl; int from = it - g.g.begin(); int to = it2->v; int topos = g.g[to].t; int frompos = g.g[from].t; // cout << topos << " " << frompos << endl; vector<int> out (res.begin() + topos, res.begin() + frompos + 1); std::sort(out.begin(), out.end()); if(!joined) { inter.insert(inter.begin(), out.begin(), out.end()); joined = true; } else { vector<int> tmp(inter.begin(), inter.end()); inter.clear(); std::set_intersection(out.begin(), out.end(), tmp.begin(), tmp.end(), std::back_inserter(inter)); } } if(!cycle_found) { cout << "NIE\n"; } else { cout << inter.size() << endl; if(inter.size()) { FOREACH(it, inter) cout << *it + 1<< " "; cout <<endl; } } return 0; } |