結果

問題 No.2677 Minmax Independent Set
ユーザー ecottea
提出日時 2024-03-15 22:37:48
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 301 ms / 2,000 ms
コード長 11,405 bytes
コンパイル時間 4,399 ms
コンパイル使用メモリ 259,932 KB
最終ジャッジ日時 2025-02-20 05:37:10
ジャッジサーバーID
(参考情報)
judge2 / judge2
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ファイルパターン 結果
sample AC * 3
other AC * 61
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ソースコード

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プレゼンテーションモードにする

#ifndef HIDDEN_IN_VS //
//
#define _CRT_SECURE_NO_WARNINGS
//
#include <bits/stdc++.h>
using namespace std;
//
using ll = long long; using ull = unsigned long long; // -2^63 2^63 = 9 * 10^18int -2^31 2^31 = 2 * 10^9
using pii = pair<int, int>; using pll = pair<ll, ll>; using pil = pair<int, ll>; using pli = pair<ll, int>;
using vi = vector<int>; using vvi = vector<vi>; using vvvi = vector<vvi>; using vvvvi = vector<vvvi>;
using vl = vector<ll>; using vvl = vector<vl>; using vvvl = vector<vvl>; using vvvvl = vector<vvvl>;
using vb = vector<bool>; using vvb = vector<vb>; using vvvb = vector<vvb>;
using vc = vector<char>; using vvc = vector<vc>; using vvvc = vector<vvc>;
using vd = vector<double>; using vvd = vector<vd>; using vvvd = vector<vvd>;
template <class T> using priority_queue_rev = priority_queue<T, vector<T>, greater<T>>;
using Graph = vvi;
//
const double PI = acos(-1);
const vi DX = { 1, 0, -1, 0 }; // 4
const vi DY = { 0, 1, 0, -1 };
int INF = 1001001001; ll INFL = 4004004003104004004LL; // (int)INFL = 1010931620;
//
struct fast_io { fast_io() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(18); } } fastIOtmp;
//
#define all(a) (a).begin(), (a).end()
#define sz(x) ((int)(x).size())
#define lbpos(a, x) (int)distance((a).begin(), std::lower_bound(all(a), x))
#define ubpos(a, x) (int)distance((a).begin(), std::upper_bound(all(a), x))
#define Yes(b) {cout << ((b) ? "Yes\n" : "No\n");}
#define rep(i, n) for(int i = 0, i##_len = int(n); i < i##_len; ++i) // 0 n-1
#define repi(i, s, t) for(int i = int(s), i##_end = int(t); i <= i##_end; ++i) // s t
#define repir(i, s, t) for(int i = int(s), i##_end = int(t); i >= i##_end; --i) // s t
#define repe(v, a) for(const auto& v : (a)) // a
#define repea(v, a) for(auto& v : (a)) // a
#define repb(set, d) for(int set = 0, set##_ub = 1 << int(d); set < set##_ub; ++set) // d
#define repis(i, set) for(int i = lsb(set), bset##i = set; i >= 0; bset##i -= 1 << i, i = lsb(bset##i)) // set
#define repp(a) sort(all(a)); for(bool a##_perm = true; a##_perm; a##_perm = next_permutation(all(a))) // a
#define smod(n, m) ((((n) % (m)) + (m)) % (m)) // mod
#define uniq(a) {sort(all(a)); (a).erase(unique(all(a)), (a).end());} //
#define EXIT(a) {cout << (a) << endl; exit(0);} //
#define inQ(x, y, u, l, d, r) ((u) <= (x) && (l) <= (y) && (x) < (d) && (y) < (r)) //
//
template <class T> inline ll powi(T n, int k) { ll v = 1; rep(i, k) v *= n; return v; }
template <class T> inline bool chmax(T& M, const T& x) { if (M < x) { M = x; return true; } return false; } // true
    
template <class T> inline bool chmin(T& m, const T& x) { if (m > x) { m = x; return true; } return false; } // true
    
template <class T> inline T get(T set, int i) { return (set >> i) & T(1); }
//
template <class T, class U> inline istream& operator>>(istream& is, pair<T, U>& p) { is >> p.first >> p.second; return is; }
template <class T> inline istream& operator>>(istream& is, vector<T>& v) { repea(x, v) is >> x; return is; }
template <class T> inline vector<T>& operator--(vector<T>& v) { repea(x, v) --x; return v; }
template <class T> inline vector<T>& operator++(vector<T>& v) { repea(x, v) ++x; return v; }
#endif //
#if __has_include(<atcoder/all>)
#include <atcoder/all>
using namespace atcoder;
#ifdef _MSC_VER
#include "localACL.hpp"
#endif
//using mint = modint1000000007;
using mint = modint998244353;
//using mint = modint; // mint::set_mod(m);
namespace atcoder {
inline istream& operator>>(istream& is, mint& x) { ll x_; is >> x_; x = x_; return is; }
inline ostream& operator<<(ostream& os, const mint& x) { os << x.val(); return os; }
}
using vm = vector<mint>; using vvm = vector<vm>; using vvvm = vector<vvm>; using vvvvm = vector<vvvm>; using pim = pair<int, mint>;
#endif
#ifdef _MSC_VER // Visual Studio
#include "local.hpp"
#else // gcc
inline int popcount(int n) { return __builtin_popcount(n); }
inline int popcount(ll n) { return __builtin_popcountll(n); }
inline int lsb(int n) { return n != 0 ? __builtin_ctz(n) : -1; }
inline int lsb(ll n) { return n != 0 ? __builtin_ctzll(n) : -1; }
inline int msb(int n) { return n != 0 ? (31 - __builtin_clz(n)) : -1; }
inline int msb(ll n) { return n != 0 ? (63 - __builtin_clzll(n)) : -1; }
#define dump(...)
#define dumpel(v)
#define dump_list(v)
#define dump_mat(v)
#define input_from_file(f)
#define output_to_file(f)
#define Assert(b) { if (!(b)) while (1) cout << "OLE"; }
#endif
//O(n + m)
/*
* (, ) n m
*
* n :
* m : n-1
* directed : false
* zero_indexed : 0-indexed false
*/
Graph read_Graph(int n, int m = -1, bool directed = false, bool zero_indexed = false) {
// verify : https://atcoder.jp/contests/tessoku-book/tasks/tessoku_book_bi
Graph g(n);
if (m == -1) m = n - 1;
rep(j, m) {
int a, b;
cin >> a >> b;
if (!zero_indexed) { --a; --b; }
g[a].push_back(b);
if (!directed && a != b) g[b].push_back(a);
}
return g;
}
// DPO(n)
/*
* g s∈[0..n)
* g s
* s∈[0..n) s tj
* s-t t sub[s][j]
*
* T merge(T x, T y, int s) :
* s 2 x, y
* s
*
* T leaf(int s) :
* g s s
*
* T apply(T x, int p, int s) :
* s x
* p→s p
*/
template <class T, T(*merge)(T, T, int), T(*leaf)(int), T(*apply)(T, int, int)>
vector<T> rerooting(const Graph& g, vector<vector<T>>* sub = nullptr) {
// : https://atcoder.jp/contests/abc222/editorial/2749
int n = sz(g);
vector<T> res(n);
// sub[s][i] : s i t
// s-t t
if (sub == nullptr) sub = new vector<vector<T>>;
sub->resize(n);
rep(s, n) (*sub)[s] = vector<T>(sz(g[s]));
// 1
if (n == 1) return vector<T>{ leaf(0) };
// p-s s
// p : 0 s
// si : s p
function<void(int, int, int)> dfs1 = [&](int s, int p, int si) {
// is_leaf : s
bool is_leaf = true;
rep(ti, sz(g[s])) {
int t = g[s][ti];
if (t == p) continue;
// s-t t
dfs1(t, s, ti);
// s→t
T val = apply((*sub)[s][ti], s, t);
//
if (p != -1) {
if (is_leaf) (*sub)[p][si] = move(val);
else (*sub)[p][si] = merge((*sub)[p][si], val, s);
}
is_leaf = false;
}
// s
if (is_leaf && p != -1) (*sub)[p][si] = leaf(s);
};
dfs1(0, -1, -1);
// s
// p : 0 s
// val : s-p p
function<void(int, int, const T&)> dfs2 = [&](int s, int p, const T& val) {
// K : s
int K = sz(g[s]);
// ds[i] : s i s
vector<T> ds(K);
rep(ti, K) {
const auto& t = g[s][ti];
if (t == p) {
(*sub)[s][ti] = val;
ds[ti] = apply(val, s, p);
continue;
}
// s-t t
// s→t s
ds[ti] = apply((*sub)[s][ti], s, t);
}
// acc_l[i] : s [0..i] s
vector<T> acc_l(K);
acc_l[0] = ds[0];
repi(i, 1, K - 1) acc_l[i] = merge(acc_l[i - 1], ds[i], s);
// acc_r[i] : s [i..K) s
vector<T> acc_r(K);
acc_r[K - 1] = ds[K - 1];
repir(i, K - 2, 0) acc_r[i] = merge(acc_r[i + 1], ds[i], s);
// s s
res[s] = acc_l[K - 1];
rep(ti, K) {
const auto& t = g[s][ti];
if (t == p) continue;
// s s→t
// t-s s
if (K == 1) dfs2(t, s, leaf(s));
else if (ti == 0) dfs2(t, s, acc_r[1]);
else if (ti == K - 1) dfs2(t, s, acc_l[K - 2]);
else dfs2(t, s, merge(acc_l[ti - 1], acc_r[ti + 1], s));
}
};
dfs2(0, -1, T()); // 1
return res;
/*
using T = int;
T merge(T x, T y, int s) {
return max(x, y);
}
T leaf(int s) {
return 0;
}
T apply(T x, int p, int s) {
return x + 1;
}
vector<T> solve_by_rerooting(const Graph& g, vector<vector<T>>* sub = nullptr) {
return rerooting<T, merge, leaf, apply>(g, sub);
}
*/
};
//O(n)
/*
* g
*
* DP
*/
using T_mis = pii; // ()
T_mis merge_mis(T_mis x, T_mis y, int s) { x.first += y.first - 1; x.second += y.second; return x; }
T_mis leaf_mis(int s) { return { 1, 0 }; }
T_mis apply_mis(T_mis x, int s, int t) { return { x.second + 1, max(x.first, x.second) }; }
void maximum_independent_set(const Graph& g) {
// verify : https://yukicoder.me/problems/no/763
auto dp = rerooting<T_mis, merge_mis, leaf_mis, apply_mis>(g);
int res = INF;
rep(i, sz(g)) chmin(res, dp[i].first);
cout << res << endl;
}
int main() {
// input_from_file("input.txt");
// output_to_file("output.txt");
int n;
cin >> n;
auto g = read_Graph(n);
maximum_independent_set(g);
}
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