#include <iostream> #include <cstring> #include <vector> #include <stack> #include <list> using namespace std; const int SIZE = 500000+15; bool visited[SIZE]; vector<int> graph[SIZE]; int k[SIZE]; // krotnosc stack<int> S; bool findCycle(int s, int w) { visited[w] = true; S.push(w); for(int i=graph[w].size()-1; i>=0; --i) { if(graph[w][i] == s) return true; if(visited[graph[w][i]] == false && findCycle(s, graph[w][i]) == true) return true; } S.pop(); return false; } int main() { ios_base::sync_with_stdio(false); memset(k, 0, sizeof(k)); int n, m; cin >> n >> m; int a, b; for(int i=0; i<m; ++i) { cin >> a >> b; graph[a].push_back(b); } int out = 0; for(int i=1; i<=n; ++i) { memset(visited, false, sizeof(visited)); S = stack<int>(); findCycle(i, i); //cout << i << ": "; if(!S.empty()) out++; while(!S.empty()) { //cout << S.top() << " "; k[S.top()]++; S.pop(); } //cout << endl; } if(out == 0) { cout << "NIE" << endl; return 0; } list<int> z; for(int i=1; i<=n; ++i) { if(k[i] == out) { z.push_back(i); } } if(z.size() > 0) { cout << z.size() << endl; for(list<int>::iterator it=z.begin(); it!=z.end(); ++it) { cout << *it << " "; } cout << endl; } else { cout << "NIE" << 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 | #include <iostream> #include <cstring> #include <vector> #include <stack> #include <list> using namespace std; const int SIZE = 500000+15; bool visited[SIZE]; vector<int> graph[SIZE]; int k[SIZE]; // krotnosc stack<int> S; bool findCycle(int s, int w) { visited[w] = true; S.push(w); for(int i=graph[w].size()-1; i>=0; --i) { if(graph[w][i] == s) return true; if(visited[graph[w][i]] == false && findCycle(s, graph[w][i]) == true) return true; } S.pop(); return false; } int main() { ios_base::sync_with_stdio(false); memset(k, 0, sizeof(k)); int n, m; cin >> n >> m; int a, b; for(int i=0; i<m; ++i) { cin >> a >> b; graph[a].push_back(b); } int out = 0; for(int i=1; i<=n; ++i) { memset(visited, false, sizeof(visited)); S = stack<int>(); findCycle(i, i); //cout << i << ": "; if(!S.empty()) out++; while(!S.empty()) { //cout << S.top() << " "; k[S.top()]++; S.pop(); } //cout << endl; } if(out == 0) { cout << "NIE" << endl; return 0; } list<int> z; for(int i=1; i<=n; ++i) { if(k[i] == out) { z.push_back(i); } } if(z.size() > 0) { cout << z.size() << endl; for(list<int>::iterator it=z.begin(); it!=z.end(); ++it) { cout << *it << " "; } cout << endl; } else { cout << "NIE" << endl; } return 0; } |