Submission #435843

#	Time	Username	Problem	Language	Result	Execution time	Memory
435843		Noam527	Keys (IOI21_keys)	C++17	9 / 100	836 ms	125504 KiB

keys

#include <bits/stdc++.h>
typedef long long ll;
typedef long double ldb;
const int md = 1e9 + 7;
const ll inf = 3e18;
const int OO = 0;
using namespace std;

const int N = 3e5 + 5;

struct group {
	int root;
	int state; // 0,1,2
	int cursed; // 0,1
	set<pair<int, int>> e;
	set<int> k;
	vector<int> q;
	group() {}
	int work() {
		while (q.size()) {
			int ke = q.back();
			auto it = e.lower_bound(make_pair(ke, -1));
			if (it != e.end() && it->first == ke) {
				int res = it->second;
				e.erase(it);
				return res;
			}
			q.pop_back();
		}
		return -1;
	}
};

int par[N];
group groups[N];

int root(int x) {
	if (x == par[x]) return x;
	return par[x] = root(par[x]);
}

void merge(group &G, group &H) {
	par[H.root] = G.root;
	if (G.q.size() < H.q.size()) {
		swap(G.q, H.q);
	}
	if (G.e.size() < H.e.size()) {
		swap(G.e, H.e);
	}
	if (G.k.size() < H.k.size()) {
		swap(G.k, H.k);
	}

	G.cursed = max(G.cursed, H.cursed);
	for (const auto &i : H.q)
		G.q.push_back(i);
	H.q.clear();
	for (const auto &i : H.e) {
		if (G.k.count(i.first) || H.k.count(i.first)) {
			G.q.push_back(i.first);
		}
		G.e.insert(i);
	}
	H.e.clear();
	for (const auto &i : H.k) {
		auto it = G.e.lower_bound(make_pair(i, -1));
		auto it2 = H.e.lower_bound(make_pair(i, -1));
		if ((it != G.e.end() && it->first == i) || (it2 != H.e.end() && it2->first == i)) {
			G.q.push_back(i);
		}
		G.k.insert(i);
	}
	H.k.clear();
}



vector<int> find_reachable(vector<int> r, vector<int> u, vector<int> v, vector<int> c) {
	int n = r.size(), m = u.size();
	for (int i = 0; i <= n; i++)
		par[i] = i;
	for (int i = 0; i < n; i++) {
		groups[i].root = i;
		groups[i].state = 0;
		groups[i].cursed = 0;
		groups[i].k.insert(r[i]);
		groups[i].q.push_back(r[i]);
	}
	for (int i = 0; i < m; i++) {
		groups[u[i]].e.insert(make_pair(c[i], v[i]));
		groups[v[i]].e.insert(make_pair(c[i], u[i]));
	}
	groups[n].root = n;
	groups[n].state = 1;
	groups[n].cursed = 1;
	groups[n].k.insert(0);
	groups[n].q.push_back(0);
	for (int i = 0; i < n; i++)
		groups[n].e.insert(groups[n].e.end(), make_pair(0, i));
	
	vector<int> stack = { n };
	while (stack.size()) {
		if (OO) {
			cout << "stack: ";
			for (const auto &i : stack) cout << i << " "; cout << '\n';
		}
		int r = stack.back();
		int v = groups[r].work();
		if (OO) {
			cout << "r, v: " << r << " " << v << '\n';
		}
		if (v == -1) {
			groups[r].state = 2;
			stack.pop_back();
			if (stack.size())
				groups[stack.back()].cursed = 1;
			continue;
		}
		v = root(v);
		if (OO) {
			cout << "root of v: " << v << '\n';
		}
		if (groups[v].state == 2) {
			if (OO) cout << "visited already :(\n";
			groups[r].cursed = 1;
			continue;
		}
		if (groups[v].state == 0) {
			if (OO) cout << "new!\n";
			groups[v].state = 1;
			stack.push_back(v);
			continue;
		}
		// cycle :)
		if (v == r) {
			if (OO) cout << "dumb cycle :(\n";
			// stupid cycle :(
			continue;
		}
		if (OO) cout << "good cycle\n";
		while (groups[stack.back()].root != v) {
			stack.pop_back();
			merge(groups[stack.back()], groups[r]);
		}
		if (OO) cout << '\n';
	}

	vector<vector<int>> clusters(n);
	for (int i = 0; i < n; i++) {
		int r = root(i);
		if (groups[r].cursed == 0)
			clusters[r].push_back(i);
	}
	int mnsize = md;
	for (int i = 0; i < n; i++)
		if (clusters[i].size()) mnsize = min(mnsize, (int)clusters[i].size());
	vector<int> result(n, 0);
	for (int i = 0; i < n; i++) {
		if (clusters[i].size() == mnsize) {
			for (const auto &j : clusters[i])
				result[j] = 1;
		}
	}
	return result;
}

/*
void solve() {
	int n, m;
	cin >> n >> m;
	vector<int> r(n), u(m), v(m), c(m);
	for (auto &i : r) cin >> i;
	for (auto &i : u) cin >> i;
	for (auto &i : v) cin >> i;
	for (auto &i : c) cin >> i;
	for (const auto &i : find_reachable(r, u, v, c))
		cout << i << " "; cout << '\n';
}

int main() {
	//ios::sync_with_stdio(0), cin.tie(0);
	int tst = 1;
	//cin >> tst;
	while (tst--) solve();
}
*/

Compilation message (stderr)

keys.cpp: In function 'std::vector<int> find_reachable(std::vector<int>, std::vector<int>, std::vector<int>, std::vector<int>)':
keys.cpp:105:4: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  105 |    for (const auto &i : stack) cout << i << " "; cout << '\n';
      |    ^~~
keys.cpp:105:50: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
  105 |    for (const auto &i : stack) cout << i << " "; cout << '\n';
      |                                                  ^~~~
keys.cpp:159:26: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  159 |   if (clusters[i].size() == mnsize) {
      |       ~~~~~~~~~~~~~~~~~~~^~~~~~~~~

• Subtask 1: 9 / 9
• Subtask 2: 0 / 11
• Subtask 3: 0 / 17
• Subtask 4: 0 / 30
• Subtask 5: 0 / 33