#include <bits/stdc++.h>
using namespace std;
#ifdef evenvalue
#include "debug.h"
#define debug(...) print(#__VA_ARGS__, __VA_ARGS__)
#else
#define debug(...)
#endif
using int64 = long long;
using ld = long double;
template<typename T>
using min_heap = priority_queue<T, vector<T>, greater<T>>;
template<typename T>
using max_heap = priority_queue<T, vector<T>, less<T>>;
namespace read {
int Int() {
int x;
cin >> x;
return x;
}
int64 Int64() {
int64 x;
cin >> x;
return x;
}
char Char() {
char c;
cin >> c;
return c;
}
string String() {
string s;
cin >> s;
return s;
}
double Double() {
return stod(String());
}
ld LongDouble() {
return stold(String());
}
template<typename T1, typename T2>
pair<T1, T2> Pair() {
pair<T1, T2> p;
cin >> p.first >> p.second;
return p;
}
template<typename T>
vector<T> Vec(const int n) {
vector<T> v(n);
for (T &x : v) {
cin >> x;
}
return v;
}
template<typename T>
vector<vector<T>> VecVec(const int n, const int m) {
vector<vector<T>> v(n);
for (vector<T> &vec : v) {
vec = Vec<T>(m);
}
return v;
}
}//namespace read
constexpr int kInf = 1e9 + 10;
constexpr int64 kInf64 = 1e15 + 10;
constexpr int kMod = 1e9 + 7;
constexpr int kMaxN = 2e5 + 10;
pair<int, int> diameter(const vector<vector<int>> &g) {
auto bfs = [&](int start) -> pair<int, int> {
const int n = g.size();
vector<int> d(n, 0);
vector<bool> visit(n, false);
queue<int> q;
q.push(start);
while (not q.empty()) {
int x = q.front();
q.pop();
visit[x] = true;
for (int nbr : g[x]) {
if (visit[nbr]) continue;
q.push(nbr);
d[nbr] = d[x] + 1;
}
}
int far = distance(d.begin(), max_element(d.begin(), d.end()));
return {d[far], far};
};
int x = bfs(0).second;
return make_pair(x, bfs(x).second);
}
inline void solution() {
const int n = read::Int();
const int m = read::Int();
if (m != n - 1) {
cout << "NO\n";
return;
}
vector<vector<int>> g(n);
for (int i = 0; i < n - 1; i++) {
const int x = read::Int() - 1;
const int y = read::Int() - 1;
g[x].push_back(y);
g[y].push_back(x);
}
const auto ends = diameter(g);
const int s = ends.first;
const int t = ends.second;
vector<int> ds(n);
vector<int> dt(n);
function<void(int, int, vector<int> &)> calc_dist = [&](const int x, const int p, vector<int> &d) {
for (const int y : g[x]) {
if (y == p) continue;
d[y] = d[x] + 1;
calc_dist(y, x, d);
}
};
calc_dist(s, -1, ds);
calc_dist(t, -1, dt);
for (int x = 0; x < n; x++) {
sort(g[x].begin(), g[x].end(), [&](const int y, const int z) {
return ds[y] + dt[y] != ds[t];
});
}
vector<int> order;
bool bad_star = false;
function<void(int, int, int)> dfs = [&](const int x, const int p, int deviate_depth) {
deviate_depth += (ds[x] + dt[x] != ds[t]);
if (deviate_depth == 3) bad_star = true;
for (const int y : g[x]) {
if (y == p) continue;
order.push_back(x);
dfs(y, x, deviate_depth);
}
};
dfs(s, -1, 0);
for (int i = order.size() - 1; i > 0; i--) {
order.push_back(order[i]);
}
if (bad_star) {
cout << "NO\n";
return;
}
cout << "YES\n";
cout << order.size() << '\n';
for (const int x : order) {
cout << x + 1 << ' ';
}
}
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
//freopen(".in", "r", stdin);
//freopen(".out", "w", stdout);
cout << fixed << setprecision(10);
int testcases = 1;
//cin >> testcases;
while (testcases--) {
solution();
}
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
0 ms |
344 KB |
Integer parameter [name=k] equals to 0, violates the range [1, 5] |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
0 ms |
360 KB |
Integer parameter [name=k] equals to 0, violates the range [1, 5] |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
0 ms |
344 KB |
Integer parameter [name=k] equals to 0, violates the range [1, 5] |
| 2 |
Halted |
0 ms |
0 KB |
- |
