This documentation is automatically generated by online-judge-tools/verification-helper
// competitive-verifier: PROBLEM https://yukicoder.me/problems/no/583
#include "../../template/template.hpp"
#include "../../graph/others/eulerian-trail.hpp"
int main() {
int N, M;
cin >> N >> M;
vector< int > A(M), B(M);
EulerianTrail< false > et(N);
for(int i = 0; i < M; i++) {
cin >> A[i] >> B[i];
et.add_edge(A[i], B[i]);
}
if(et.enumerate_semi_eulerian_trail().size() == 1) cout << "YES\n";
else cout << "NO\n";
}
#line 1 "test/verify/yukicoder-583.test.cpp"
// competitive-verifier: PROBLEM https://yukicoder.me/problems/no/583
#line 1 "template/template.hpp"
#include <bits/stdc++.h>
using namespace std;
using int64 = long long;
const int64 infll = (1LL << 62) - 1;
const int inf = (1 << 30) - 1;
struct IoSetup {
IoSetup() {
cin.tie(nullptr);
ios::sync_with_stdio(false);
cout << fixed << setprecision(10);
cerr << fixed << setprecision(10);
}
} iosetup;
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
os << p.first << " " << p.second;
return os;
}
template <typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) {
is >> p.first >> p.second;
return is;
}
template <typename T>
ostream &operator<<(ostream &os, const vector<T> &v) {
for (int i = 0; i < (int)v.size(); i++) {
os << v[i] << (i + 1 != v.size() ? " " : "");
}
return os;
}
template <typename T>
istream &operator>>(istream &is, vector<T> &v) {
for (T &in : v) is >> in;
return is;
}
template <typename T1, typename T2>
inline bool chmax(T1 &a, T2 b) {
return a < b && (a = b, true);
}
template <typename T1, typename T2>
inline bool chmin(T1 &a, T2 b) {
return a > b && (a = b, true);
}
template <typename T = int64>
vector<T> make_v(size_t a) {
return vector<T>(a);
}
template <typename T, typename... Ts>
auto make_v(size_t a, Ts... ts) {
return vector<decltype(make_v<T>(ts...))>(a, make_v<T>(ts...));
}
template <typename T, typename V>
typename enable_if<is_class<T>::value == 0>::type fill_v(T &t, const V &v) {
t = v;
}
template <typename T, typename V>
typename enable_if<is_class<T>::value != 0>::type fill_v(T &t, const V &v) {
for (auto &e : t) fill_v(e, v);
}
template <typename F>
struct FixPoint : F {
explicit FixPoint(F &&f) : F(forward<F>(f)) {}
template <typename... Args>
decltype(auto) operator()(Args &&...args) const {
return F::operator()(*this, forward<Args>(args)...);
}
};
template <typename F>
inline decltype(auto) MFP(F &&f) {
return FixPoint<F>{forward<F>(f)};
}
#line 4 "test/verify/yukicoder-583.test.cpp"
#line 2 "graph/others/eulerian-trail.hpp"
#line 2 "structure/union-find/union-find.hpp"
struct UnionFind {
vector<int> data;
UnionFind() = default;
explicit UnionFind(size_t sz) : data(sz, -1) {}
bool unite(int x, int y) {
x = find(x), y = find(y);
if (x == y) return false;
if (data[x] > data[y]) swap(x, y);
data[x] += data[y];
data[y] = x;
return true;
}
int find(int k) {
if (data[k] < 0) return (k);
return data[k] = find(data[k]);
}
int size(int k) { return -data[find(k)]; }
bool same(int x, int y) { return find(x) == find(y); }
vector<vector<int> > groups() {
int n = (int)data.size();
vector<vector<int> > ret(n);
for (int i = 0; i < n; i++) {
ret[find(i)].emplace_back(i);
}
ret.erase(remove_if(begin(ret), end(ret),
[&](const vector<int> &v) { return v.empty(); }),
end(ret));
return ret;
}
};
#line 4 "graph/others/eulerian-trail.hpp"
/**
* @brief Eulerian Trail(オイラー路)
*
*/
template <bool directed>
struct EulerianTrail {
vector<vector<pair<int, int> > > g;
vector<pair<int, int> > es;
int M;
vector<int> used_vertex, used_edge, deg;
explicit EulerianTrail(int V) : g(V), M(0), used_vertex(V), deg(V) {}
void add_edge(int a, int b) {
es.emplace_back(a, b);
g[a].emplace_back(b, M);
if (directed) {
deg[a]++;
deg[b]--;
} else {
g[b].emplace_back(a, M);
deg[a]++;
deg[b]++;
}
M++;
}
pair<int, int> get_edge(int idx) const { return es[idx]; }
vector<vector<int> > enumerate_eulerian_trail() {
if (directed) {
for (auto &p : deg)
if (p != 0) return {};
} else {
for (auto &p : deg)
if (p & 1) return {};
}
used_edge.assign(M, 0);
vector<vector<int> > ret;
for (int i = 0; i < (int)g.size(); i++) {
if (g[i].empty() || used_vertex[i]) continue;
ret.emplace_back(go(i));
}
return ret;
}
vector<vector<int> > enumerate_semi_eulerian_trail() {
UnionFind uf(g.size());
for (auto &p : es) uf.unite(p.first, p.second);
vector<vector<int> > group(g.size());
for (int i = 0; i < (int)g.size(); i++) group[uf.find(i)].emplace_back(i);
vector<vector<int> > ret;
used_edge.assign(M, 0);
for (auto &vs : group) {
if (vs.empty()) continue;
int latte = -1, malta = -1;
if (directed) {
for (auto &p : vs) {
if (abs(deg[p]) > 1) {
return {};
} else if (deg[p] == 1) {
if (latte >= 0) return {};
latte = p;
}
}
} else {
for (auto &p : vs) {
if (deg[p] & 1) {
if (latte == -1)
latte = p;
else if (malta == -1)
malta = p;
else
return {};
}
}
}
ret.emplace_back(go(latte == -1 ? vs.front() : latte));
if (ret.back().empty()) ret.pop_back();
}
return ret;
}
vector<int> go(int s) {
stack<pair<int, int> > st;
vector<int> ord;
st.emplace(s, -1);
while (!st.empty()) {
int idx = st.top().first;
used_vertex[idx] = true;
if (g[idx].empty()) {
ord.emplace_back(st.top().second);
st.pop();
} else {
auto e = g[idx].back();
g[idx].pop_back();
if (used_edge[e.second]) continue;
used_edge[e.second] = true;
st.emplace(e);
}
}
ord.pop_back();
reverse(ord.begin(), ord.end());
return ord;
}
};
#line 6 "test/verify/yukicoder-583.test.cpp"
int main() {
int N, M;
cin >> N >> M;
vector< int > A(M), B(M);
EulerianTrail< false > et(N);
for(int i = 0; i < M; i++) {
cin >> A[i] >> B[i];
et.add_edge(A[i], B[i]);
}
if(et.enumerate_semi_eulerian_trail().size() == 1) cout << "YES\n";
else cout << "NO\n";
}
Env | Name | Status | Elapsed | Memory |
---|---|---|---|---|
g++ | sample1.txt | AC | 6 ms | 4 MB |
g++ | sample2.txt | AC | 6 ms | 4 MB |
g++ | sample3.txt | AC | 6 ms | 4 MB |
g++ | test1.txt | AC | 6 ms | 4 MB |
g++ | test10.txt | AC | 11 ms | 5 MB |
g++ | test11.txt | AC | 11 ms | 5 MB |
g++ | test12.txt | AC | 11 ms | 5 MB |
g++ | test13.txt | AC | 12 ms | 6 MB |
g++ | test14.txt | AC | 18 ms | 8 MB |
g++ | test15.txt | AC | 20 ms | 8 MB |
g++ | test16.txt | AC | 24 ms | 10 MB |
g++ | test2.txt | AC | 6 ms | 4 MB |
g++ | test3.txt | AC | 6 ms | 4 MB |
g++ | test4.txt | AC | 6 ms | 4 MB |
g++ | test5.txt | AC | 6 ms | 4 MB |
g++ | test6.txt | AC | 6 ms | 4 MB |
g++ | test7.txt | AC | 6 ms | 4 MB |
g++ | test8.txt | AC | 6 ms | 4 MB |
g++ | test9.txt | AC | 10 ms | 5 MB |
clang++ | sample1.txt | AC | 6 ms | 4 MB |
clang++ | sample2.txt | AC | 6 ms | 4 MB |
clang++ | sample3.txt | AC | 6 ms | 4 MB |
clang++ | test1.txt | AC | 6 ms | 4 MB |
clang++ | test10.txt | AC | 11 ms | 5 MB |
clang++ | test11.txt | AC | 11 ms | 5 MB |
clang++ | test12.txt | AC | 11 ms | 5 MB |
clang++ | test13.txt | AC | 12 ms | 6 MB |
clang++ | test14.txt | AC | 18 ms | 7 MB |
clang++ | test15.txt | AC | 21 ms | 8 MB |
clang++ | test16.txt | AC | 26 ms | 10 MB |
clang++ | test2.txt | AC | 7 ms | 4 MB |
clang++ | test3.txt | AC | 6 ms | 4 MB |
clang++ | test4.txt | AC | 6 ms | 4 MB |
clang++ | test5.txt | AC | 6 ms | 4 MB |
clang++ | test6.txt | AC | 6 ms | 4 MB |
clang++ | test7.txt | AC | 6 ms | 4 MB |
clang++ | test8.txt | AC | 6 ms | 4 MB |
clang++ | test9.txt | AC | 9 ms | 5 MB |