結果
| 問題 | No.1424 Ultrapalindrome |
| ユーザー |
 nok0
|
| 提出日時 | 2020-12-30 22:02:40 |
| 言語 | C++17 (gcc 12.3.0 + boost 1.83.0) |
| 結果 |
WA
|
| 実行時間 | - |
| コード長 | 19,754 bytes |
| コンパイル時間 | 2,865 ms |
| コンパイル使用メモリ | 239,220 KB |
| 実行使用メモリ | 32,280 KB |
| 最終ジャッジ日時 | 2024-05-03 09:04:39 |
| 合計ジャッジ時間 | 4,691 ms |
|
ジャッジサーバーID （参考情報） |
judge2 / judge4 |
（要ログイン）
テストケース
テストケース表示| 入力 | 結果 | 実行時間 実行使用メモリ |
|---|---|---|
| testcase_00 | AC | 2 ms
5,248 KB |
| testcase_01 | AC | 2 ms
5,376 KB |
| testcase_02 | WA | - |
| testcase_03 | WA | - |
| testcase_04 | AC | 2 ms
5,376 KB |
| testcase_05 | AC | 2 ms
5,376 KB |
| testcase_06 | AC | 2 ms
5,376 KB |
| testcase_07 | AC | 2 ms
5,376 KB |
| testcase_08 | AC | 2 ms
5,376 KB |
| testcase_09 | AC | 43 ms
10,960 KB |
| testcase_10 | AC | 50 ms
10,972 KB |
| testcase_11 | AC | 31 ms
8,660 KB |
| testcase_12 | AC | 39 ms
10,960 KB |
| testcase_13 | AC | 11 ms
5,376 KB |
| testcase_14 | AC | 35 ms
9,104 KB |
| testcase_15 | AC | 2 ms
5,376 KB |
| testcase_16 | AC | 25 ms
7,816 KB |
| testcase_17 | AC | 30 ms
8,708 KB |
| testcase_18 | AC | 30 ms
10,488 KB |
| testcase_19 | AC | 60 ms
13,464 KB |
| testcase_20 | AC | 11 ms
6,016 KB |
| testcase_21 | AC | 38 ms
12,092 KB |
| testcase_22 | AC | 22 ms
8,356 KB |
| testcase_23 | AC | 5 ms
5,376 KB |
| testcase_24 | AC | 10 ms
5,632 KB |
| testcase_25 | AC | 9 ms
5,632 KB |
| testcase_26 | AC | 67 ms
16,960 KB |
| testcase_27 | AC | 54 ms
12,868 KB |
| testcase_28 | WA | - |
| testcase_29 | AC | 62 ms
32,280 KB |
| testcase_30 | AC | 40 ms
21,484 KB |
| testcase_31 | AC | 43 ms
21,532 KB |
ソースコード
/**
* author: nok0
* created: 2020.12.30 21:50:20
**/
#ifdef LOCAL
#define _GLIBCXX_DEBUG
#endif
#include <bits/stdc++.h>
using namespace std;
#pragma region Macros
#define FOR(i, l, r) for(int i = (l); i < (r); ++i)
#define REP(i, n) FOR(i, 0, n)
#define REPS(i, n) FOR(i, 1, n + 1)
#define RFOR(i, l, r) for(int i = (l); i >= (r); --i)
#define RREP(i, n) RFOR(i, n - 1, 0)
#define RREPS(i, n) RFOR(i, n, 1)
#define pb push_back
#define eb emplace_back
#define SZ(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
template <class T = int>
using V = vector<T>;
template <class T = int>
using VV = V<V<T>>;
using ll = long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
#define VEC(type, name, size) \
V<type> name(size); \
INPUT(name)
#define VVEC(type, name, h, w) \
VV<type> name(h, V<type>(w)); \
INPUT(name)
#define INT(...) \
int __VA_ARGS__; \
INPUT(__VA_ARGS__)
#define LL(...) \
ll __VA_ARGS__; \
INPUT(__VA_ARGS__)
#define STR(...) \
string __VA_ARGS__; \
INPUT(__VA_ARGS__)
#define CHAR(...) \
char __VA_ARGS__; \
INPUT(__VA_ARGS__)
#define DOUBLE(...) \
DOUBLE __VA_ARGS__; \
INPUT(__VA_ARGS__)
#define LD(...) \
LD __VA_ARGS__; \
INPUT(__VA_ARGS__)
void scan(int &a) { cin >> a; }
void scan(long long &a) { cin >> a; }
void scan(char &a) { cin >> a; }
void scan(double &a) { cin >> a; }
void scan(long double &a) { cin >> a; }
void scan(char a[]) { scanf("%s", a); }
void scan(string &a) { cin >> a; }
template <class T>
void scan(V<T> &);
template <class T, class L>
void scan(pair<T, L> &);
template <class T>
void scan(V<T> &a) {
for(auto &i : a) scan(i);
}
template <class T, class L>
void scan(pair<T, L> &p) {
scan(p.first);
scan(p.second);
}
template <class T>
void scan(T &a) { cin >> a; }
void INPUT() {}
template <class Head, class... Tail>
void INPUT(Head &head, Tail &... tail) {
scan(head);
INPUT(tail...);
}
template <class T>
inline void print(T x) { cout << x << '\n'; }
template <typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) {
is >> p.first >> p.second;
return is;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
os << p.first << " " << p.second;
return os;
}
template <typename T>
istream &operator>>(istream &is, vector<T> &v) {
for(T &in : v) is >> in;
return is;
}
template <class T>
ostream &operator<<(ostream &os, const V<T> &v) {
REP(i, SZ(v)) {
if(i) os << " ";
os << v[i];
}
return os;
}
//debug
template <typename T>
void view(const V<T> &v) {
cerr << "{ ";
for(const auto &e : v) {
cerr << e << ", ";
}
cerr << "\b\b }";
}
template <typename T>
void view(const VV<T> &vv) {
cerr << "{\n";
for(const auto &v : vv) {
cerr << "\t";
view(v);
cerr << "\n";
}
cerr << "}";
}
template <typename T, typename U>
void view(const V<pair<T, U>> &v) {
cerr << "{\n";
for(const auto &c : v) cerr << "\t(" << c.first << ", " << c.second << ")\n";
cerr << "}";
}
template <typename T, typename U>
void view(const map<T, U> &m) {
cerr << "{\n";
for(auto &t : m) cerr << "\t[" << t.first << "] : " << t.second << "\n";
cerr << "}";
}
template <typename T, typename U>
void view(const pair<T, U> &p) { cerr << "(" << p.first << ", " << p.second << ")"; }
template <typename T>
void view(const set<T> &s) {
cerr << "{ ";
for(auto &t : s) {
view(t);
cerr << ", ";
}
cerr << "\b\b }";
}
template <typename T>
void view(T e) { cerr << e; }
#ifdef LOCAL
void debug_out() {}
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
view(H);
cerr << ", ";
debug_out(T...);
}
#define debug(...) \
do { \
cerr << __LINE__ << " [" << #__VA_ARGS__ << "] : ["; \
debug_out(__VA_ARGS__); \
cerr << "\b\b]\n"; \
} while(0)
#else
#define debug(...) (void(0))
#endif
template <class T>
V<T> press(V<T> &x) {
V<T> res = x;
sort(all(res));
res.erase(unique(all(res)), res.end());
REP(i, SZ(x)) {
x[i] = lower_bound(all(res), x[i]) - res.begin();
}
return res;
}
template <class T>
inline bool chmin(T &a, T b) {
if(a > b) {
a = b;
return true;
}
return false;
}
template <class T>
inline bool chmax(T &a, T b) {
if(a < b) {
a = b;
return true;
}
return false;
}
inline void Yes(bool b = true) { cout << (b ? "Yes" : "No") << '\n'; }
inline void YES(bool b = true) { cout << (b ? "YES" : "NO") << '\n'; }
inline void err(bool b = true) {
if(b) {
cout << -1 << '\n';
exit(0);
}
}
template <class T>
inline void fin(bool b = true, T e = 0) {
if(b) {
cout << e << '\n';
exit(0);
}
}
template <class T>
T divup(T x, T y) { return (x + (y - 1)) / y; }
template <typename T>
T pow(T a, long long n, T e = 1) {
T ret = e;
while(n) {
if(n & 1) ret *= a;
a *= a;
n >>= 1;
}
return ret;
}
struct iofast {
iofast() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
cout << fixed << setprecision(15);
}
} iofast_;
const int inf = 1e9;
const ll INF = 1e18;
#pragma endregion
struct Edge {
int to;
long long cost;
Edge() = default;
Edge(int to_, long long cost_)
: to(to_), cost(cost_) {}
bool operator<(const Edge &a) const {
return cost < a.cost;
}
bool operator>(const Edge &a) const {
return cost > a.cost;
}
friend std::ostream &operator<<(std::ostream &s, Edge &a) {
s << "to:" << a.to << " cost:" << a.cost;
return s;
}
};
struct Graph : private std::vector<std::vector<Edge>> {
using std::vector<std::vector<Edge>>::vector;
using std::vector<std::vector<Edge>>::operator[];
using std::vector<std::vector<Edge>>::operator=;
using std::vector<std::vector<Edge>>::size;
using std::vector<std::vector<Edge>>::resize;
using std::vector<std::vector<Edge>>::clear;
using std::vector<std::vector<Edge>>::push_back;
using std::vector<std::vector<Edge>>::emplace_back;
using std::vector<std::vector<Edge>>::begin;
using std::vector<std::vector<Edge>>::end;
private:
const long long INF = 1e18;
std::vector<std::pair<int, int>> edges;
std::vector<std::tuple<int, int, long long>> cedges;
bool isweight = true, lcainit_done = false;
std::vector<std::vector<int>> parent;
std::vector<int> lcadist;
template <class T>
inline bool chmax(T &a, T b) {
if(a < b) {
a = b;
return true;
}
return false;
}
template <class T>
inline bool chmin(T &a, T b) {
if(a > b) {
a = b;
return true;
}
return false;
}
public:
void read(int e = -1, bool weight = 0, bool directed = false, int idx = 1) {
if(e == -1) e = size() - 1;
if(!weight) isweight = false;
while(e--) {
int u, v;
long long cost = 1;
std::cin >> u >> v;
if(weight) std::cin >> cost;
u -= idx, v -= idx;
(*this)[u].emplace_back(v, cost);
edges.emplace_back(u, v);
cedges.emplace_back(u, v, cost);
if(!directed) (*this)[v].emplace_back(u, cost);
}
}
void add(int u, int v, int cost = -1, bool directed = false, int idx = 0) {
if(cost != -1)
isweight = true;
else
cost = 1;
u -= idx, v -= idx;
(*this)[u].emplace_back(v, cost);
edges.emplace_back(u, v);
cedges.emplace_back(u, v, cost);
if(!directed) (*this)[v].emplace_back(u, cost);
}
std::vector<long long> Dijkstra(int s) {
std::vector dist(size(), INF);
if(isweight) {
using pll = std::pair<long long, long long>;
std::priority_queue<pll, std::vector<pll>, std::greater<pll>> que;
dist[s] = 0;
que.push(pll(0, s));
while(!que.empty()) {
pll p = que.top();
que.pop();
int v = p.second;
if(dist[v] < p.first) continue;
for(int i = 0; i < int((*this)[v].size()); i++) {
Edge e = (*this)[v][i];
if(dist[e.to] > dist[v] + e.cost) {
dist[e.to] = dist[v] + e.cost;
que.push(pll(dist[e.to], e.to));
}
}
}
return dist;
} else {
std::vector dist(size(), INF);
std::queue<int> que;
dist[s] = 0;
que.push(s);
while(!que.empty()) {
int v = que.front();
que.pop();
for(auto nv : (*this)[v]) {
if(dist[nv.to] != INF) continue;
dist[nv.to] = dist[v] + 1;
que.push(nv.to);
}
}
return dist;
}
}
std::vector<long long> BellmanFord(int s) {
int n = size();
std::vector res(n, INF);
res[s] = 0;
for(int loop = 0; loop < n - 1; loop++) {
for(int v = 0; v < n; v++) {
if(res[v] == INF) continue;
for(auto &e : (*this)[v]) {
res[e.to] = std::min(res[e.to], res[v] + e.cost);
}
}
}
std::queue<int> que;
std::vector chk(n, 0);
for(int v = 0; v < n; v++) {
if(res[v] == INF) continue;
for(auto &e : (*this)[v]) {
if(res[e.to] > res[v] + e.cost) {
res[e.to] = res[v] + e.cost;
if(!chk[e.to]) {
que.push(e.to);
chk[e.to] = 1;
}
}
}
}
while(!que.empty()) {
int now = que.front();
que.pop();
for(auto &e : (*this)[now]) {
if(!chk[e.to]) {
chk[e.to] = 1;
que.push(e.to);
}
}
}
for(int i = 0; i < n; i++)
if(chk[i]) res[i] = -INF;
return res;
}
std::vector<std::vector<long long>> WarshallFloyd() {
int n = size();
std::vector dist(n, std::vector(n, INF));
for(int i = 0; i < n; i++) {
dist[i][i] = 0;
}
for(int i = 0; i < n; i++) {
for(auto e : (*this)[i]) {
chmin(dist[i][e.to], e.cost);
}
}
for(int k = 0; k < n; k++)
for(int i = 0; i < n; i++)
for(int j = 0; j < n; j++)
chmin(dist[i][j], dist[i][k] + dist[k][j]);
return dist;
}
int lca(int u, int v) {
std::function<void(int, int, int)> dfs = [&](int now, int per, int d) {
parent[0][now] = per;
lcadist[now] = d;
for(auto &e : (*this)[now])
if(e.to != per) dfs(e.to, now, d + 1);
};
if(!lcainit_done) {
lcainit_done = true;
int n = size();
int k = 1;
while((1 << k) < n) k++;
parent.assign(k, std::vector(n, -1));
lcadist.assign(n, -1);
dfs(0, -1, 0);
for(int i = 0; i < k - 1; i++)
for(int v = 0; v < n; v++) {
if(parent[i][v] < 0)
parent[i + 1][v] = -1;
else
parent[i + 1][v] = parent[i][parent[i][v]];
}
}
if(lcadist[u] < lcadist[v]) std::swap(u, v);
int k = parent.size();
for(int i = 0; i < k; i++)
if((lcadist[u] - lcadist[v]) >> i & 1) u = parent[i][u];
if(u == v) return u;
for(int i = k - 1; i >= 0; i--)
if(parent[i][u] != parent[i][v])
u = parent[i][u], v = parent[i][v];
return parent[0][u];
}
int dist(int u, int v) { return lcadist[u] + lcadist[v] - 2 * lcadist[lca(u, v)]; }
std::vector<int> tsort() {
std::vector<int> res;
int n = size();
std::vector<int> used(n, 0);
bool notDAG = false;
std::function<void(int)> dfs = [&](int k) {
if(notDAG) return;
if(used[k]) {
if(used[k] == 1)
notDAG = true;
return;
}
used[k] = 1;
for(auto &e : (*this)[k]) dfs(e.to);
used[k] = 2;
res.push_back(k);
};
for(int i = 0; i < n; i++) dfs(i);
if(notDAG) return std::vector<int>{};
std::reverse(res.begin(), res.end());
return res;
}
bool isDAG() { return tsort().size(); }
std::vector<long long> height() {
std::vector<long long> fir(size(), -1), sec(size(), -1);
std::function<long long(int, int)> dfs = [&](int now, int par) {
long long f = 0, s = 0;
for(auto &e : (*this)[now]) {
if(e.to == par) continue;
s = std::max(s, dfs(e.to, now) + e.cost);
if(f < s) std::swap(f, s);
}
sec[now] = s;
return fir[now] = f;
};
std::function<void(int, int, long long, long long, long long)> solve = [&](int now, int par, long long parf, long long pars, long long parcost) {
if(fir[now] + parcost == parf) parf = pars;
sec[now] = std::max(sec[now], parf + parcost);
if(fir[now] < sec[now]) std::swap(fir[now], sec[now]);
for(auto &e : (*this)[now]) {
if(e.to == par) continue;
solve(e.to, now, fir[now], sec[now], e.cost);
}
return;
};
dfs(0, -1);
solve(0, -1, -1, -1, -1);
return fir;
}
//{二部グラフか、二部グラフのどちらに属するかを0か1で表した配列}
std::pair<bool, std::vector<int>> isBiparate() {
std::vector<int> colors(size()), ret(size());
std::function<bool(int, int)> dfs = [&](int now, int col) {
colors[now] = col;
if(col == 1) ret[now] = 1;
for(auto &e : (*this)[now]) {
if(col == colors[e.to]) return false;
if(colors[e.to] == 0 and !dfs(e.to, -col)) return false;
}
return true;
};
return std::pair(dfs(0, 1), ret);
}
//{{端点、端点},直径の大きさ}
std::pair<std::pair<int, int>, long long> Diameter() {
auto vec = Dijkstra(0);
int v1 = -1, v2 = -1;
long long dia = -1;
for(int i = 0; i < int(size()); i++)
if(chmax(dia, vec[i]))
v1 = i;
vec = Dijkstra(v1);
dia = -1;
for(int i = 0; i < int(size()); i++)
if(chmax(dia, vec[i]))
v2 = i;
std::pair<std::pair<int, int>, long long> res = {{v1, v2}, dia};
return res;
}
//最小全域木
long long Prim() {
long long res = 0;
std::priority_queue<Edge, std::vector<Edge>, std::greater<Edge>> que;
for(auto &e : (*this)[0])
que.push(e);
std::vector chk(size(), 0);
chk[0] = 1;
while(!que.empty()) {
auto e = que.top();
que.pop();
if(chk[e.to]) continue;
res += e.cost;
chk[e.to] = 1;
for(auto &e : (*this)[e.to]) {
que.push(e);
}
}
return res;
}
//重心
std::vector<int> Centroid() {
int n = size();
std::vector<int> centroid, sz(n);
std::function<void(int, int)> dfs = [&](int now, int per) {
sz[now] = 1;
bool is_centroid = true;
for(auto &e : (*this)[now])
if(e.to != per) {
dfs(e.to, now);
sz[now] += sz[e.to];
if(sz[e.to] > n / 2) is_centroid = false;
}
if(n - sz[now] > n / 2) is_centroid = false;
if(is_centroid) centroid.push_back(now);
};
return centroid;
}
//pair{橋(pairの配列),関節点(intの配列)}
std::pair<std::vector<std::pair<int, int>>, std::vector<int>> lowlink() {
int n = size(), k = 0;
std::vector<int> used(n, 0), order(n, 0), low(n, 0), articulation;
std::vector<std::pair<int, int>> bridge;
std::function<int(int, int, int)> dfs = [&](int idx, int k, int par) {
used[idx] = 1;
order[idx] = k++;
low[idx] = order[idx];
bool is_articulation = false, neko = false;
int cnt = 0;
for(auto &e : (*this)[idx]) {
if(e.to == par and !std::exchange(neko, true)) {
continue;
}
if(!used[e.to]) {
++cnt;
k = dfs(e.to, k, idx);
low[idx] = std::min(low[idx], low[e.to]);
is_articulation |= par >= 0 and low[e.to] >= order[idx];
if(order[idx] < low[e.to]) {
auto p = std::minmax(idx, e.to);
bridge.emplace_back(p.first, p.second);
}
} else {
low[idx] = std::min(low[idx], order[e.to]);
}
}
is_articulation |= par == -1 and cnt > 1;
if(is_articulation) articulation.push_back(idx);
return k;
};
for(int i = 0; i < n; i++)
if(!used[i]) k = dfs(i, k, -1);
return std::pair(bridge, articulation);
}
//根から葉への有向グラフ
Graph RootToLeaf(int root = 0) {
Graph res(size());
std::vector chk(size(), 0);
chk[root] = 1;
std::function<void(int)> dfs = [&](int now) {
for(auto &e : (*this)[now]) {
if(chk[e.to] == 1) continue;
chk[e.to] = 1;
res.add(now, e.to, e.cost, 1, 0);
dfs(e.to);
}
};
dfs(root);
return res;
}
//葉から根への有向グラフ
Graph LeafToRoot(int root = 0) {
Graph res(size());
std::vector chk(size(), 0);
chk[root] = 1;
std::function<void(int)> dfs = [&](int now) {
for(auto &e : (*this)[now]) {
if(chk[e.to] == 1) continue;
chk[e.to] = 1;
res.add(e.to, now, e.cost, 1, 0);
dfs(e.to);
}
};
dfs(root);
return res;
}
//辺(from,to)を返す
std::vector<std::pair<int, int>> getedges() {
return edges;
}
//辺(from,to,cost)を返す
std::vector<std::tuple<int, int, long long>> getwedges() {
return cedges;
}
};
struct SCC {
private:
const Graph &g;
Graph ng, rg;
std::vector<int> compo, order, used;
void dfs(int now) {
if(used[now]) return;
used[now] = true;
for(auto &e : ng[now]) dfs(e.to);
order.emplace_back(now);
}
void rdfs(int now, int count) {
if(compo[now] != -1) return;
compo[now] = count;
for(auto &e : rg[now]) rdfs(e.to, count);
}
public:
SCC(Graph &g_) : g(g_) {
int n = g.size();
ng.resize(n);
rg.resize(n);
compo.assign(n, -1);
used.resize(n);
for(int i = 0; i < n; i++) {
for(auto &e : g[i]) {
ng[i].emplace_back(e.to, 1);
rg[e.to].emplace_back(i, 1);
}
}
}
int operator[](int k) { return compo[k]; }
Graph build() {
Graph ret;
for(int i = 0; i < (int)ng.size(); i++)
dfs(i);
reverse(order.begin(), order.end());
int group = 0;
for(auto i : order)
if(compo[i] == -1) rdfs(i, group), group++;
ret.resize(group);
for(int i = 0; i < (int)g.size(); i++) {
for(auto &e : g[i]) {
int s = compo[i], t = compo[e.to];
if(s != t) ret[s].emplace_back(t, 1);
}
}
return std::move(ret);
}
};
struct HeavyLightDecomposition {
public:
std::vector<int> sz, in, out, head, rev, par;
private:
Graph &g;
void dfs_sz(int v, int p = -1) {
par[v] = p;
if(!g[v].empty() and g[v].front().to == p)
std::swap(g[v].front(), g[v].back());
for(auto &e : g[v]) {
if(e.to == p) continue;
dfs_sz(e.to, v);
sz[v] += sz[e.to];
if(sz[g[v].front().to] < sz[e.to])
std::swap(g[v].front(), e);
}
}
void dfs_hld(int v, int &t, int p = -1) {
in[v] = t++;
rev[in[v]] = v;
for(auto &e : g[v]) {
if(e.to == p) continue;
head[e.to] = (g[v].front().to == e.to ? head[v] : e.to);
dfs_hld(e.to, t, v);
}
out[v] = t;
}
void build(int root = 0) {
dfs_sz(root);
int t = 0;
head[root] = root;
dfs_hld(root, t);
}
public:
HeavyLightDecomposition(Graph &g_, int root = 0) : g(g_) {
int n = g.size();
sz.assign(n, 1);
in.resize(n);
out.resize(n);
head.resize(n);
rev.resize(n);
par.resize(n);
build(root);
}
//頂点vから0方向にk遡った頂点を返す
int la(int v, int k) {
while(true) {
int u = head[v];
if(in[v] - k >= in[u]) return rev[in[v] - k];
k -= in[v] - in[u] + 1;
v = par[u];
}
}
int lca(int u, int v) {
for(;; v = par[head[v]]) {
if(in[u] > in[v]) std::swap(u, v);
if(head[u] == head[v]) return u;
}
}
//u,v:頂点 ti:単位元 q:列にたいするクエリ f:列のmerge
template <typename T, typename Q, typename F>
T query(int u, int v, const T &ti, const Q &q, const F &f, bool edge = false) {
T l = ti, r = ti;
for(;; v = par[head[v]]) {
if(in[u] > in[v]) std::swap(u, v), std::swap(l, r);
if(head[u] == head[v]) break;
l = f(q(in[head[v]], in[v] + 1), l);
}
return f(f(q(in[u] + edge, in[v] + 1), l), r);
}
//u,v:頂点 q:更新クエリ
template <typename Q>
void add(int u, int v, const Q &q, bool edge = false) {
for(;; v = par[head[v]]) {
if(in[u] > in[v]) std::swap(u, v);
if(head[u] == head[v]) break;
q(in[head[v]], in[v] + 1);
}
q(in[u] + edge, in[v] + 1);
}
std::pair<int, int> subtree(int v, bool edge = false) {
return std::pair<int, int>(in[v] + edge, out[v]);
}
};
int main() {
INT(n);
Graph G(n);
G.read();
int center = -1;
REP(i, n) {
if(SZ(G[i]) > 2) {
if(center == -1)
center = i;
else {
Yes(0);
return 0;
}
}
}
if(center == -1){
Yes(0);
return 0;
}
Graph H = G.RootToLeaf(center);
auto dfs = [&H](auto self, int now) -> int {
int ret = 0;
if(SZ(H[now]) > 1)
return -inf;
for(auto &[to, ig] : H[now])
ret += self(self, to) + 1;
return ret;
};
int tmp = dfs(dfs, H[center][0].to);
bool ok = true;
for(auto &[to, ig] : H[center])
if(tmp != dfs(dfs, to)) ok = false;
Yes(ok);
return 0;
}