Submission #680082

#	Time	Username	Problem	Language	Result	Execution time	Memory
680082		SanguineChameleon	Dynamic Diameter (CEOI19_diameter)	C++17	100 / 100	3351 ms	168956 KiB

diameter

// 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

struct range {
	int root = 0;
	int pos = 0;
	int lt = 0;
	int rt = 0;

	range() {

	}

	range(int _root, int _pos, int _lt, int _rt) {
		root = _root;
		pos = _pos;
		lt = _lt;
		rt = _rt;
	}
};

struct tree {
	vector<long long> tr;
	vector<long long> lz;
	int n = 0;

	tree() {

	}

	tree(int _n) {
		n = _n;
		tr.resize(n << 2);
		lz.resize(n << 2);
	}

	void push(int cc) {
		tr[cc << 1] += lz[cc];
		lz[cc << 1] += lz[cc];
		tr[cc << 1 | 1] += lz[cc];
		lz[cc << 1 | 1] += lz[cc];
		lz[cc] = 0;
	}

	void update(int cc, int lt, int rt, int ql, int qr, long long pp) {
		if (lt == ql && rt == qr) {
			tr[cc] += pp;
			lz[cc] += pp;
			return;
		}
		push(cc);
		int mt = (lt + rt) / 2;
		if (qr <= mt) {
			update(cc << 1, lt, mt, ql, qr, pp);
		}
		else if (ql >= mt + 1) {
			update(cc << 1 | 1, mt + 1, rt, ql, qr, pp);
		}
		else {
			update(cc << 1, lt, mt, ql, mt, pp);
			update(cc << 1 | 1, mt + 1, rt, mt + 1, qr, pp);
		}
		tr[cc] = max(tr[cc << 1], tr[cc << 1 | 1]);
	}
};

const int ms = 1e5 + 20;
bool f[ms];
int sz[ms];
long long W[ms];
vector<pair<int, int>> adj[ms];
int pt[ms][2];
int tz;
multiset<long long, greater<long long>> S;
multiset<long long, greater<long long>> best[ms];
vector<range> R[ms];
vector<tree> T[ms];

void dfs1(int u, int pr) {
	sz[u] = 1;
	for (auto x: adj[u]) {
		int v = x.first;
		if (!f[v] && v != pr) {
			dfs1(v, u);
			sz[u] += sz[v];
		}
	}
}

int ctr(int u, int pr, int root) {
	for (auto x: adj[u]) {
		int v = x.first;
		if (!f[v] && v != pr) {
			if (sz[v] * 2 > sz[root]) {
				return ctr(v, u, root);
			}
		}
	}
	return u;
}

void dfs2(int u, int pr, int root, int pos) {
	pt[u][0] = ++tz;
	sz[u] = 1;
	for (auto x: adj[u]) {
		int v = x.first;
		int id = x.second;
		if (!f[v] && v != pr) {
			dfs2(v, u, root, pos);
			R[id].emplace_back(root, pos, pt[v][0], pt[v][1]);
			sz[u] += sz[v];
		}
	}
	pt[u][1] = tz;
}

void build(int u) {
	dfs1(u, -1);
	u = ctr(u, -1, u);
	f[u] = true;
	int cnt = 0;
	for (auto x: adj[u]) {
		int v = x.first;
		int id = x.second;
		if (!f[v]) {
			tz = 0;
			dfs2(v, -1, u, cnt);
			R[id].emplace_back(u, cnt, pt[v][0], pt[v][1]);
			cnt++;
			T[u].emplace_back(sz[v]);
			best[u].insert(0);
		}
	}
	for (auto x: adj[u]) {
		int v = x.first;
		if (!f[v]) {
			build(v);
		}
	}
}

long long get(int u) {
	long long res = 0;
	auto it = best[u].begin();
	if (it == best[u].end()) {
		return res;
	}
	res += (*it);
	it++;
	if (it == best[u].end()) {
		return res;
	}
	res += (*it);
	return res;
}

void update(range r, long long pp) {
	int root = r.root;
	int pos = r.pos;
	int lt = r.lt;
	int rt = r.rt;
	S.erase(S.find(get(root)));
	tree &t = T[root][pos];
	best[root].erase(best[root].find(t.tr[1]));
	t.update(1, 1, t.n, lt, rt, pp);
	best[root].insert(t.tr[1]);
	S.insert(get(root));
}


void just_do_it() {
	int n, q;
	long long lim;
	cin >> n >> q >> lim;
	for (int i = 0; i < n; i++) {
		S.insert(0);
	}
	for (int i = 0; i < n - 1; i++) {
		int u, v;
		cin >> u >> v >> W[i];
		adj[u].emplace_back(v, i);
		adj[v].emplace_back(u, i);
	}
	build(1);
	for (int i = 0; i < n - 1; i++) {
		for (auto r: R[i]) {
			update(r, W[i]);
		}
	}
	long long res = 0;
	for (int i = 0; i < q; i++) {
		int id;
		long long w;
		cin >> id >> w;
		id = (res + id) % (n - 1);
		w = (res + w) % lim;
		for (auto r: R[id]) {
			update(r, w - W[id]);
		}
		W[id] = w;
		res = *S.begin();
		cout << res << '\n';
	}
}

// END MAIN CODE

Compilation message (stderr)

diameter.cpp: In function 'void file_io(std::string, std::string)':
diameter.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);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
diameter.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: 11 / 11
• Subtask 2: 13 / 13
• Subtask 3: 7 / 7
• Subtask 4: 18 / 18
• Subtask 5: 24 / 24
• Subtask 6: 27 / 27