This documentation is automatically generated by online-judge-tools/verification-helper
#define PROBLEM \
"https://onlinejudge.u-aizu.ac.jp/courses/library/5/GRL/4/GRL_4_A"
#include <bits/stdc++.h>
using namespace std;
#include "../../src/search/bfs/has_directed_cycle.hpp"
int main() {
int V, E;
cin >> V >> E;
vector<vector<int>> g(V);
for (int i = 0; i < E; ++i) {
int s, t;
cin >> s >> t;
g[s].push_back(t);
}
auto res = has_directed_cycle(g);
cout << (res ? 1 : 0) << endl;
return 0;
}
#line 1 "test/aoj/grl_4_a_2.test.cpp"
#define PROBLEM \
"https://onlinejudge.u-aizu.ac.jp/courses/library/5/GRL/4/GRL_4_A"
#include <bits/stdc++.h>
using namespace std;
#line 2 "src/search/bfs/has_directed_cycle.hpp"
#line 4 "src/search/bfs/has_directed_cycle.hpp"
using namespace std;
#line 2 "src/search/bfs/topological_sort.hpp"
#line 4 "src/search/bfs/topological_sort.hpp"
using namespace std;
vector<int> topological_sort(const vector<vector<int>> &g) {
int n = g.size();
vector<int> deg(n);
for (int i = 0; i < n; ++i) {
for (int to : g[i]) {
++deg[to];
}
}
queue<int> que;
for (int i = 0; i < n; ++i) {
if (deg[i] == 0) {
que.push(i);
}
}
vector<int> res;
while (!que.empty()) {
int v = que.front();
que.pop();
res.push_back(v);
for (int to : g[v]) {
--deg[to];
if (deg[to] == 0) {
que.push(to);
}
}
}
return res;
}
#line 7 "src/search/bfs/has_directed_cycle.hpp"
bool has_directed_cycle(const vector<vector<int>> &g) {
vector<int> orders = topological_sort(g);
int n = g.size();
return (int)orders.size() != n;
}
#line 8 "test/aoj/grl_4_a_2.test.cpp"
int main() {
int V, E;
cin >> V >> E;
vector<vector<int>> g(V);
for (int i = 0; i < E; ++i) {
int s, t;
cin >> s >> t;
g[s].push_back(t);
}
auto res = has_directed_cycle(g);
cout << (res ? 1 : 0) << endl;
return 0;
}