Submission #496234

#	Time	Username	Problem	Language	Result	Execution time	Memory
496234		hollwo_pelw	Meetings 2 (JOI21_meetings2)	C++17	100 / 100	234 ms	57332 KiB

meetings2

/*
// is short or still long ???
hollwo_pelw's template(short)
// Note : -Dhollwo_pelw_local
*/

#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/trie_policy.hpp>
// #include <ext/rope>

using namespace std;
// using namespace __gnu_pbds;
// using namespace __gnu_cxx;

void FAST_IO(string filein = "", string fileout = "", string fileerr = ""){
	if (fopen(filein.c_str(), "r")){
		freopen(filein.c_str(), "r", stdin);
		freopen(fileout.c_str(), "w", stdout);
#ifdef hollwo_pelw_local
		freopen(fileerr.c_str(), "w", stderr);
#endif
	}
	cin.tie(0), cout.tie(0) -> sync_with_stdio(0);
}

void Hollwo_Pelw();

signed main(){
#ifdef hollwo_pelw_local
	FAST_IO("input.inp", "output.out", "error.err");
	auto start = chrono::steady_clock::now();
#else
	FAST_IO("hollwo_pelw.inp", "hollwo_pelw.out");
#endif
	int testcases = 1;
	// cin >> testcases;
	for (int test = 1; test <= testcases; test++){
		// cout << "Case #" << test << ": ";
		Hollwo_Pelw();
	}
#ifdef hollwo_pelw_local
	auto end = chrono::steady_clock::now();
	cout << "\nExcution time : " << chrono::duration_cast<chrono::milliseconds> (end - start).count() << "[ms]" << endl;
#endif
	return 0;
}

const int N = 2e5 + 5, L = 20;

vector<int> adj[N];

struct calc_dist {
	template<class T, const T& merge(const T&, const T&)> struct rmq {
		vector<T> st[L];
		rmq () {}
		rmq (const vector<T> &a) {
			st[0] = a; int n = a.size(); __build__(n);
		}
		rmq (T * __first, T * __last) {
			st[0] = vector<T> (__first, __last);
			int n = __last - __first; __build__(n);
		}
 
		inline void __build__(int n) {
			for (int j = 1; 1 << j <= n; j++) {
				st[j].resize(n - (1 << j) + 1);
				for (int i = 0; i + (1 << j) <= n; i++)
					st[j][i] = merge(st[j - 1][i], st[j - 1][i + (1 << j - 1)]);
			}
		}
 
		inline T query(int l, int r) {
			int j = __lg(r - l + 1);
			// return merge(st[j][l], st[j][r - (1 << j) + 1]); // 0 base
			return merge(st[j][l - 1], st[j][r - (1 << j)]); // 1 base
		}
	};
 
	rmq<int, min<int>> rmq_dist;
 
	int d[N], val[N << 1], tin[N], timer;
 
	void pre_dfs(int u, int p) {
		val[tin[u] = ++ timer] = d[u];
		for (int v : adj[u]) if (v != p) {
			d[v] = d[u] + 1;
			pre_dfs(v, u);
			val[++ timer] = d[u];
		}
	}
 
	inline void __init__() {
		pre_dfs(1, 0);
		rmq_dist = rmq<int, min<int>> (val + 1, val + timer + 1);
	}
 
	inline int operator () (int u, int v) {
		int l = tin[u], r = tin[v]; if (l > r) swap(l, r);
		return d[u] + d[v] - 2 * rmq_dist.query(l, r);
	}
} dist;

int n, res[N], sz[N], vis[N], deg[N];
vector<int> leaf[N];

inline int solve(int sz) {
	vector<int> lf;
	for (int i = sz; i <= n; i++)
		lf.insert(lf.end(), leaf[i].begin(), leaf[i].end());

	if (lf.empty()) return 1;

	int d1 = lf[0], d2 = lf[0];

	for (auto v : lf) {
		if (dist(d1, v) > dist(d1, d2))
			d2 = v;
	}

	for (auto v : lf) {
		if (dist(d2, v) > dist(d1, d2))
			d1 = v;
	}

	return dist(d1, d2) + 1;
}

void Hollwo_Pelw() {
	cin >> n;
	for (int i = 1, u, v; i < n; i++)
		cin >> u >> v, adj[u].push_back(v), adj[v].push_back(u);

	dist.__init__();

	fill(sz + 1, sz + n + 1, 1);
	for (int i = 1; i <= n; i++) {
		if (adj[i].size() == 1 + deg[i])
			vis[i] = 1, leaf[1].push_back(i);
	}

	for (int i = 1; i <= n; i++) for (auto u : leaf[i]) {
		for (auto v : adj[u]) if (!vis[v]) {
			sz[v] += sz[u];
			++ deg[v];

			if (adj[v].size() == 1 + deg[v])
				vis[v] = 1, leaf[sz[v]].push_back(v);
		}
	}

	fill(res + 1, res + n + 1, 1);

	int d1 = -1, d2 = -1;

	for (int i = n; i >= 1; i--) for (auto v : leaf[i]) {
		if (d1 == -1) d1 = v;
		if (d2 == -1) d2 = v;

		if (dist(v, d2) > dist(d1, d2)) d1 = v;
		if (dist(d1, v) > dist(d1, d2)) d2 = v;

		int j = min(sz[d1], sz[d2]) * 2;

		res[j] = max(res[j], dist(d1, d2) + 1);
	}

	for (int j = n - n % 2; j > 2; j -= 2)
		res[j - 2] = max(res[j - 2], res[j]);

	for (int i = 1; i <= n; i++)
		cout << res[i] << '\n';
}

Compilation message (stderr)

meetings2.cpp: In function 'void Hollwo_Pelw()':
meetings2.cpp:138:21: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  138 |   if (adj[i].size() == 1 + deg[i])
      |       ~~~~~~~~~~~~~~^~~~~~~~~~~~~
meetings2.cpp:147:22: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  147 |    if (adj[v].size() == 1 + deg[v])
      |        ~~~~~~~~~~~~~~^~~~~~~~~~~~~
meetings2.cpp: In instantiation of 'void calc_dist::rmq<T, merge>::__build__(int) [with T = int; const T& (* merge)(const T&, const T&) = std::min<int>]':
meetings2.cpp:62:30:   required from 'calc_dist::rmq<T, merge>::rmq(T*, T*) [with T = int; const T& (* merge)(const T&, const T&) = std::min<int>]'
meetings2.cpp:95:58:   required from here
meetings2.cpp:69:59: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
   69 |      st[j][i] = merge(st[j - 1][i], st[j - 1][i + (1 << j - 1)]);
      |                                                         ~~^~~
meetings2.cpp: In function 'void FAST_IO(std::string, std::string, std::string)':
meetings2.cpp:18:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   18 |   freopen(filein.c_str(), "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
meetings2.cpp:19:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   19 |   freopen(fileout.c_str(), "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 16 / 16
• Subtask 3: 80 / 80