Submission #677206

#	Time	Username	Problem	Language	Result	Execution time	Memory
677206		SanguineChameleon	Hard route (IZhO17_road)	C++17	100 / 100	1006 ms	198860 KiB

road

// BEGIN BOILERPLATE CODE

#include <bits/stdc++.h>
using namespace std;

#ifdef KAMIRULEZ
	const bool kami_loc = true;
	const long long kami_seed = 69420;
#else
	const bool kami_loc = false;
	const long long kami_seed = chrono::steady_clock::now().time_since_epoch().count();
#endif

const string kami_fi = "kamirulez.inp";
const string kami_fo = "kamirulez.out";
mt19937_64 kami_gen(kami_seed);

long long rand_range(long long rmin, long long rmax) {
	uniform_int_distribution<long long> rdist(rmin, rmax);
	return rdist(kami_gen);
}

long double rand_real(long double rmin, long double rmax) {
	uniform_real_distribution<long double> rdist(rmin, rmax);
	return rdist(kami_gen);
}

void file_io(string fi, string fo) {
	if (fi != "" && (!kami_loc || fi == kami_fi)) {
		freopen(fi.c_str(), "r", stdin);
	}
	if (fo != "" && (!kami_loc || fo == kami_fo)) {
		freopen(fo.c_str(), "w", stdout);
	}
}

void set_up() {
	if (kami_loc) {
		file_io(kami_fi, kami_fo);
	}
	ios_base::sync_with_stdio(0);
	cin.tie(0);
}

void just_do_it();

void just_exec_it() {
	if (kami_loc) {
		auto pstart = chrono::steady_clock::now();
		just_do_it();
		auto pend = chrono::steady_clock::now();
		long long ptime = chrono::duration_cast<chrono::milliseconds>(pend - pstart).count();
		string bar(50, '=');
		cout << '\n' << bar << '\n';
		cout << "Time: " << ptime << " ms" << '\n';
	}
	else {
		just_do_it();
	}
}

int main() {
	set_up();
	just_exec_it();
	return 0;
}

// END BOILERPLATE CODE

// BEGIN MAIN CODE

const int ms = 5e5 + 20;
const int inf = 1e9 + 20;
vector<int> adj[ms];
pair<long long, long long> res = {0, 1};

pair<int, int> operator+(pair<int, int> x, int d) {
	return {x.first + d, x.second};
}

pair<long long, long long> max(pair<long long, long long> x, pair<long long, long long> y) {
	if (x.first > y.first) {
		return x;
	}
	else if (x.first < y.first) {
		return y;
	}
	else {
		return {x.first, x.second + y.second};
	}
}

struct chunk {
	int sz = 0;
	long long s1 = 0;
	long long s2 = 0;

	void add(int x) {
		sz++;
		s1 += x;
		s2 += 1LL * x * x;
	}

	void rem(int x) {
		sz--;
		s1 -= x;
		s2 -= 1LL * x * x;
	}

	long long get1() {
		return s1;
	}

	long long get2() {
		return (s1 * s1 - s2) / 2;
	}
};

struct group {
	map<int, chunk, greater<int>> f;

	void add(pair<int, int> x) {
		f[x.first].add(x.second);
	}

	void rem(pair<int, int> x) {
		auto it = f.find(x.first);
		it->second.rem(x.second);
		if (it->second.sz == 0) {
			f.erase(it);
		}
	}

	pair<int, int> best() {
		return {f.begin()->first, f.begin()->second.s1};
	}

	void calc() {
		auto it = f.begin();
		if (it == f.end()) {
			return;
		}
		int x1 = it->first;
		if (x1 == 0) {
			return;
		}
		chunk &p1 = it->second;
		if (p1.sz >= 3) {
			res = max(res, make_pair(1LL * x1 * (x1 + x1), p1.get2()));
			return;
		}
		it++;
		if (it == f.end()) {
			return;
		}
		int x2 = it->first;
		if (x2 == 0) {
			return;
		}
		chunk &p2 = it->second;
		if (p1.sz >= 2) {
			res = max(res, make_pair(1LL * x1 * (x1 + x2), p1.get1() * p2.get1()));
			return;
		}
		if (p2.sz >= 2) {
			res = max(res, make_pair(1LL * x1 * (x2 + x2), p2.get2()));
			return;
		}
		it++;
		if (it == f.end()) {
			return;
		}
		int x3 = it->first;
		if (x3 == 0) {
			return;
		}
		chunk &p3 = it->second;
		res = max(res, make_pair(1LL * x1 * (x2 + x3), p2.get1() * p3.get1()));
		return;
	}
};

group g[ms];

void dfs1(int u, int pr) {
	g[u].add({0, 1});
	for (auto v: adj[u]) {
		if (v != pr) {
			dfs1(v, u);
			g[u].add(g[v].best() + 1);
		}
	}
}

void dfs2(int u, int pr) {
	g[u].calc();
	for (auto v: adj[u]) {
		if (v != pr) {
			g[u].rem(g[v].best() + 1);
			g[v].add(g[u].best() + 1);
			dfs2(v, u);
			g[v].rem(g[u].best() + 1);
			g[u].add(g[v].best() + 1);
		}
	}
}

void just_do_it() {
	int n;
	cin >> n;
	for (int i = 0; i < n - 1; i++) {
		int u, v;
		cin >> u >> v;
		adj[u].push_back(v);
		adj[v].push_back(u);
	}
	dfs1(1, -1);
	dfs2(1, -1);
	cout << res.first << " " << res.second;
}

// END MAIN CODE

Compilation message (stderr)

road.cpp: In function 'void file_io(std::string, std::string)':
road.cpp:30:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |   freopen(fi.c_str(), "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
road.cpp:33:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |   freopen(fo.c_str(), "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 19 / 19
• Subtask 2: 33 / 33
• Subtask 3: 48 / 48