結果
| 問題 |
No.806 木を道に
|
| コンテスト | |
| ユーザー |
 Pachicobue
|
| 提出日時 | 2019-03-22 21:31:58 |
| 言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
| 結果 |
WA
|
| 実行時間 | - |
| コード長 | 13,599 bytes |
| コンパイル時間 | 2,046 ms |
| コンパイル使用メモリ | 204,508 KB |
| 最終ジャッジ日時 | 2025-01-06 23:44:44 |
|
ジャッジサーバーID （参考情報） |
judge5 / judge5 |
（要ログイン）
| ファイルパターン | 結果 |
|---|---|
| sample | AC * 2 |
| other | AC * 9 WA * 18 |
ソースコード
#include <bits/stdc++.h>
#pragma GCC diagnostic ignored "-Wsign-compare"
#pragma GCC diagnostic ignored "-Wsign-conversion"
//!===========================================================!//
//! dP dP dP !//
//! 88 88 88 !//
//! 88aaaaa88a .d8888b. .d8888b. .d888b88 .d8888b. 88d888b. !//
//! 88 88 88ooood8 88' '88 88' '88 88ooood8 88' '88 !//
//! 88 88 88. ... 88. .88 88. .88 88. ... 88 !//
//! dP dP '88888P' '88888P8 '88888P8 '88888P' dP !//
//!===========================================================!//
using ld = long double;
using uint = unsigned int;
using ll = long long;
using ull = unsigned long long;
template <typename T>
constexpr T INF = std::numeric_limits<T>::max() / 4;
template <typename T>
constexpr T MOD = static_cast<T>(1000000007);
template <typename F>
constexpr F PI = static_cast<F>(3.1415926535897932385);
//! メルセンヌ・ツイスタ !//
std::mt19937 mt{std::random_device{}()};
//! Debug出力 !//
#define SHOW(...) (std::cerr << "(" << #__VA_ARGS__ << ") = ("), HogeHogeSansuu(__VA_ARGS__), std::cerr << ")" << std::endl;
struct has_debugPrint_impl
{
template <class T>
static auto check(T&& x) -> decltype(x.debugPrint(), std::true_type{});
template <class T>
static auto check(...) -> std::false_type;
};
template <class T>
class has_debugPrint : public decltype(has_debugPrint_impl::check<T>(std::declval<T>()))
{
};
template <bool>
struct HogeHogeDump
{
template <typename T>
static void dump(const T& x) { x.debugPrint(); }
};
template <>
struct HogeHogeDump<false>
{
template <typename T>
static void dump(const T& x) { std::cerr << x; }
};
void HogeHogeSansuu() { ; }
template <typename T>
void HogeHogeSansuu(const T& x) { HogeHogeDump<has_debugPrint<T>::value>::dump(x); }
template <typename T, typename... Args>
void HogeHogeSansuu(const T& x, Args... args) { HogeHogeDump<has_debugPrint<T>::value>::dump(x), std::cerr << ",", HogeHogeSansuu(args...); }
//! chminとchmax !//
template <typename T>
bool chmin(T& a, const T& b) { return a = std::min(a, b), a == b; }
template <typename T>
bool chmax(T& a, const T& b) { return a = std::max(a, b), a == b; }
//! Rep関数 !//
template <typename T, typename F>
void For(const T s, const T t, const F f)
{
for (T i = s; i != t; i += T(s < t ? 1 : -1)) { f(i); }
}
template <typename T, typename F>
void Rep(const T N, const F f) { For<T, F>(0, N, f); }
template <typename T, typename F>
void RRep(const T N, const F f) { For<T, F>(N - 1, -1, f); }
//! Vec関数 !//
template <typename T>
std::vector<T> Vec(const std::size_t n, T v) { return std::vector<T>(n, v); }
template <class... Args>
auto Vec(const std::size_t n, Args... args) { return std::vector<decltype(Vec(args...))>(n, Vec(args...)); }
//! ビット演算 !//
template <typename T>
constexpr T popCount(const T u)
{
#ifdef __has_builtin
return u == 0 ? T(0) : (T)__builtin_popcountll(u);
#else
unsigned long long v = static_cast<unsigned long long>(u);
return v = (v & 0x5555555555555555ULL) + (v >> 1 & 0x5555555555555555ULL), v = (v & 0x3333333333333333ULL) + (v >> 2 & 0x3333333333333333ULL), v = (v + (v >> 4)) & 0x0F0F0F0F0F0F0F0FULL, static_cast<T>(v * 0x0101010101010101ULL >> 56 & 0x7f);
#endif
}
template <typename T>
constexpr T log2p1(const T u)
{
#ifdef __has_builtin
return u == 0 ? T(0) : T(64 - __builtin_clzll(u));
#else
unsigned long long v = static_cast<unsigned long long>(u);
return v = static_cast<unsigned long long>(v), v |= (v >> 1), v |= (v >> 2), v |= (v >> 4), v |= (v >> 8), v |= (v >> 16), v |= (v >> 32), popCount(v);
#endif
}
template <typename T>
constexpr T clog(const T v) { return v == 0 ? T(0) : log2p1(v - 1); }
template <typename T>
constexpr T msbp1(const T v) { return log2p1(v); }
template <typename T>
constexpr T lsbp1(const T v)
{
#ifdef __has_builtin
return __builtin_ffsll(v);
#else
return v == 0 ? T(0) : popCount((v & (-v)) - T(1)) + T(1);
#endif
}
template <typename T>
constexpr bool ispow2(const T v) { return popCount(v) == 1; }
template <typename T>
constexpr T ceil2(const T v) { return v == 0 ? T(1) : T(1) << log2p1(v - 1); }
template <typename T>
constexpr T floor2(const T v) { return v == 0 ? T(0) : T(1) << (log2p1(v) - 1); }
//! 累積和 !//
template <typename T>
struct Accum
{
template <typename InIt>
Accum(const InIt first, const InIt last) : accum(std::size_t(std::distance(first, last))) { std::partial_sum(first, last, accum.begin()); }
T sum(const std::size_t i) const { return i == 0 ? T(0) : accum[i - 1]; }
T sum(const std::size_t l, const std::size_t r) const { return sum(r) - sum(l); }
std::vector<T> accum;
};
template <typename T>
struct Accum2D
{
Accum2D(const std::vector<std::vector<T>>& t) : accum{t}
{
for (std::size_t i = 0; i < accum.size(); i++) {
for (std::size_t j = 1; j < accum[i].size(); j++) { accum[i][j] += accum[i][j - 1]; }
}
for (std::size_t i = 1; i < accum.size(); i++) {
for (std::size_t j = 0; j < accum[i].size(); j++) { accum[i][j] += accum[i - 1][j]; }
}
}
T sum(const std::size_t y, const std::size_t x) const { return y == 0 or x == 0 ? T(0) : accum[y - 1][x - 1]; }
T sum(const std::size_t ymin, const std::size_t ysup, const std::size_t xmin, const std::size_t xsup) const { return sum(ysup, xsup) - sum(ymin, xmin); }
std::vector<std::vector<T>> accum;
};
//! 座標圧縮 !//
template <typename T>
struct Zip
{
template <typename InIt>
Zip(const InIt first, const InIt last) : unzip(std::size_t(std::distance(first, last)))
{
std::copy(first, last, unzip), std::sort(unzip.begin(), unzip.end()), unzip.erase(std::unique(unzip.begin(), unzip.end()), unzip.end());
for (std::size_t i = 0; i < unzip.size(); i++) { zip[unzip[i]] = i; }
}
std::vector<T> unzip;
std::map<T, std::size_t> zip;
};
//! STLの出力関数 !//
template <typename T, std::size_t N>
std::ostream& operator<<(std::ostream& os, const std::array<T, N>& v)
{
os << "[";
for (const auto& e : v) { os << e << ","; }
return (os << "]" << std::endl);
}
template <typename T, typename A>
std::ostream& operator<<(std::ostream& os, const std::deque<T, A>& v)
{
os << "[";
for (const auto& e : v) { os << e << ","; }
return (os << "]" << std::endl);
}
template <typename K, typename T, typename C, typename A>
std::ostream& operator<<(std::ostream& os, const std::multimap<K, T, C, A>& v)
{
os << "[";
for (const auto& e : v) { os << "<" << e.first << ": " << e.second << ">,"; }
return (os << "]" << std::endl);
}
template <typename T, typename C, typename A>
std::ostream& operator<<(std::ostream& os, const std::multiset<T, C, A>& v)
{
os << "[";
for (const auto& e : v) { os << e << ","; }
return (os << "]" << std::endl);
}
template <typename K, typename T, typename C, typename A>
std::ostream& operator<<(std::ostream& os, const std::map<K, T, C, A>& v)
{
os << "[";
for (const auto& e : v) { os << "<" << e.first << ": " << e.second << ">,"; }
return (os << "]" << std::endl);
}
template <typename T1, typename T2>
std::ostream& operator<<(std::ostream& os, const std::pair<T1, T2>& v) { return (os << "<" << v.first << "," << v.second << ">"); }
template <typename T1, typename T2, typename T3>
std::ostream& operator<<(std::ostream& os, const std::priority_queue<T1, T2, T3>& v)
{
auto q = v;
os << "[";
while (not q.empty()) { os << q.top() << ",", q.pop(); }
return os << "]\n";
}
template <typename T1, typename T2>
std::ostream& operator<<(std::ostream& os, const std::queue<T1>& v)
{
auto q = v;
os << "[";
while (not q.empty()) { os << q.front() << ",", q.pop(); }
return os << "]\n";
}
template <typename T, typename C, typename A>
std::ostream& operator<<(std::ostream& os, const std::set<T, C, A>& v)
{
os << "[";
for (const auto& e : v) { os << e << ","; }
return (os << "]" << std::endl);
}
template <typename T1, typename T2>
std::ostream& operator<<(std::ostream& os, const std::stack<T1>& v)
{
auto q = v;
os << "[";
while (not q.empty()) { os << q.top() << ",", q.pop(); }
return os << "]\n";
}
template <typename K, typename T, typename H, typename P, typename A>
std::ostream& operator<<(std::ostream& os, const std::unordered_multimap<K, T, H, P, A>& v)
{
os << "[";
for (const auto& e : v) { os << "<" << e.first << ": " << e.second << ">,"; }
return (os << "]" << std::endl);
}
template <typename T, typename H, typename P, typename A>
std::ostream& operator<<(std::ostream& os, const std::unordered_multiset<T, H, P, A>& v)
{
os << "[";
for (const auto& e : v) { os << e << ","; }
return (os << "]" << std::endl);
}
template <typename K, typename T, typename H, typename P, typename A>
std::ostream& operator<<(std::ostream& os, const std::unordered_map<K, T, H, P, A>& v)
{
os << "[";
for (const auto& e : v) { os << "<" << e.first << ": " << e.second << ">,"; }
return (os << "]" << std::endl);
}
template <typename T, typename H, typename P, typename A>
std::ostream& operator<<(std::ostream& os, const std::unordered_set<T, H, P, A>& v)
{
os << "[";
for (const auto& e : v) { os << e << ","; }
return (os << "]" << std::endl);
}
template <typename T, typename A>
std::ostream& operator<<(std::ostream& os, const std::vector<T, A>& v)
{
os << "[";
for (const auto& e : v) { os << e << ","; }
return (os << "]" << std::endl);
}
//!=======================================================================================!//
//! a88888b. dP .88888. dP !//
//! d8' '88 88 d8' '88 88 !//
//! 88 .d8888b. .d8888b. d8888P 88 88d888b. .d8888b. 88d888b. 88d888b. !//
//! 88 88' '88 Y8ooooo. 88 88 YP88 88' '88 88' '88 88' '88 88' '88 !//
//! Y8. .88 88. .88 88 88 Y8. .88 88 88. .88 88. .88 88 88 !//
//! Y88888P' '88888P' '88888P' dP '88888' dP '88888P8 88Y888P' dP dP !//
//! 88 !//
//! dP !//
//!=======================================================================================!//
template <typename T>
struct CostGraph
{
CostGraph(const std::size_t v) : V{v}, edge(v), rev_edge(v) {}
void addEdge(const std::size_t from, const std::size_t to, const T cost) { edge[from].push_back(Edge{to, cost}), rev_edge[to].push_back(Edge(from, cost)); }
struct Edge
{
Edge(const std::size_t to, const T cost) : to{to}, cost{cost} {}
const std::size_t to;
const T cost;
bool operator<(const Edge& e) const { return cost != e.cost ? cost < e.cost : to < e.to; }
};
const std::vector<Edge>& operator[](const std::size_t i) const { return edge[i]; }
void debugPrint() const
{
std::cerr << "[\n";
for (std::size_t i = 0; i < V; i++) {
for (const auto& e : edge[i]) { std::cerr << i << "->" << e.to << ":" << e.cost << "\n"; }
}
std::cerr << "]\n";
}
const std::size_t V;
std::vector<std::vector<Edge>> edge, rev_edge;
};
//!======================================================================!//
//! 888888ba oo dP !//
//! 88 '8b 88 !//
//! 88 88 dP .d8888b. 88d8b.d8b. .d8888b. d8888P .d8888b. 88d888b. !//
//! 88 88 88 88' '88 88''88''88 88ooood8 88 88ooood8 88' '88 !//
//! 88 .8P 88 88. .88 88 88 88 88. ... 88 88. ... 88 !//
//! 8888888P dP '88888P8 dP dP dP '88888P' dP '88888P' dP !//
//!======================================================================!//
template <typename T>
std::vector<std::size_t> Diameter(const CostGraph<T>& g)
{
const std::size_t V = g.V;
std::vector<T> dist(V, 0);
std::vector<std::size_t> p(V, V);
auto dfs = [&](auto&& self, const std::size_t s, const std::size_t prev) -> void {
for (const auto& e : g.edge[s]) {
if (e.to == prev) { continue; }
dist[e.to] = dist[s] + e.cost, p[e.to] = s;
self(self, e.to, s);
}
};
dfs(dfs, 0, V);
std::size_t r = std::max_element(dist.begin(), dist.end()) - dist.begin();
dist[r] = 0, std::fill(p.begin(), p.end(), V), dfs(dfs, r, V);
r = std::max_element(dist.begin(), dist.end()) - dist.begin();
std::vector<std::size_t> ans;
for (; r != V; r = p[r]) { ans.push_back(r); }
return ans;
}
//!============================================!//
//! 8888ba.88ba oo !//
//! 88 '8b '8b !//
//! 88 88 88 .d8888b. dP 88d888b. !//
//! 88 88 88 88' '88 88 88' '88 !//
//! 88 88 88 88. .88 88 88 88 !//
//! dP dP dP '88888P8 dP dP dP !//
//!============================================!//
int main()
{
int N;
std::cin >> N;
CostGraph<int> G(N);
for (int i = 0, u, v; i < N - 1; i++) { std::cin >> u >> v, u--, v--, G.addEdge(u, v, 1), G.addEdge(v, u, 1); }
const auto d = Diameter(G);
std::cout << N - d.size() << std::endl;
return 0;
}