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#define PROBLEM "https://judge.yosupo.jp/problem/tree_diameter" #include "../../template/template.hpp" #include "../../graph/tree/tree-diameter.hpp" int main() { int N; cin >> N; TreeDiameter< int64_t > g(N); g.read(N - 1, 0, true); cout << g.build() << " "; cout << g.path.size() + 1 << "\n"; cout << g.path[0].from << " " << g.path << "\n"; }
#line 1 "test/verify/yosupo-tree-diameter.test.cpp" #define PROBLEM "https://judge.yosupo.jp/problem/tree_diameter" #line 1 "template/template.hpp" #include<bits/stdc++.h> using namespace std; using int64 = long long; const int mod = 1e9 + 7; 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/yosupo-tree-diameter.test.cpp" #line 2 "graph/tree/tree-diameter.hpp" #line 2 "graph/graph-template.hpp" /** * @brief Graph Template(グラフテンプレート) */ template< typename T = int > struct Edge { int from, to; T cost; int idx; Edge() = default; Edge(int from, int to, T cost = 1, int idx = -1) : from(from), to(to), cost(cost), idx(idx) {} operator int() const { return to; } }; template< typename T = int > struct Graph { vector< vector< Edge< T > > > g; int es; Graph() = default; explicit Graph(int n) : g(n), es(0) {} size_t size() const { return g.size(); } void add_directed_edge(int from, int to, T cost = 1) { g[from].emplace_back(from, to, cost, es++); } void add_edge(int from, int to, T cost = 1) { g[from].emplace_back(from, to, cost, es); g[to].emplace_back(to, from, cost, es++); } void read(int M, int padding = -1, bool weighted = false, bool directed = false) { for(int i = 0; i < M; i++) { int a, b; cin >> a >> b; a += padding; b += padding; T c = T(1); if(weighted) cin >> c; if(directed) add_directed_edge(a, b, c); else add_edge(a, b, c); } } inline vector< Edge< T > > &operator[](const int &k) { return g[k]; } inline const vector< Edge< T > > &operator[](const int &k) const { return g[k]; } }; template< typename T = int > using Edges = vector< Edge< T > >; #line 4 "graph/tree/tree-diameter.hpp" /** * @brief Tree-Diameter(木の直径) * @docs docs/tree-diameter.md */ template< typename T = int > struct TreeDiameter : Graph< T > { public: using Graph< T >::Graph; using Graph< T >::g; vector< Edge< T > > path; T build() { to.assign(g.size(), -1); auto p = dfs(0, -1); auto q = dfs(p.second, -1); int now = p.second; while(now != q.second) { for(auto &e : g[now]) { if(to[now] == e.to) { path.emplace_back(e); } } now = to[now]; } return q.first; } explicit TreeDiameter(const Graph< T > &g) : Graph< T >(g) {} private: vector< int > to; pair< T, int > dfs(int idx, int par) { pair< T, int > ret(0, idx); for(auto &e : g[idx]) { if(e.to == par) continue; auto cost = dfs(e.to, idx); cost.first += e.cost; if(ret < cost) { ret = cost; to[idx] = e.to; } } return ret; } }; #line 6 "test/verify/yosupo-tree-diameter.test.cpp" int main() { int N; cin >> N; TreeDiameter< int64_t > g(N); g.read(N - 1, 0, true); cout << g.build() << " "; cout << g.path.size() + 1 << "\n"; cout << g.path[0].from << " " << g.path << "\n"; }