Submission #94950

#	Time	Username	Problem	Language	Result	Execution time	Memory
94950		noclever	Untitled (POI11_kon)	C++14	100 / 100	2341 ms	84984 KiB

Main

#include <vector>
#include <iostream>
#include <set>
#include <bitset>
#include <algorithm>
using namespace std;
 
int n;
vector< vector<short> > g, tg;
vector< bitset<5001> > mat;
vector<int> was, topoSort, scc;
vector<int> index, lowlink, s;
int cur = 1, gi = 1;
vector<int> as;
vector<int> st;
vector<short> x[2];
int cnt[2][2];
 
void add_edge(int u, int v) {
	g[u].push_back(v);
}
 
void strongconnect(int u) {
	index[u] = gi;
	lowlink[u] = gi;
	gi++;
	
	s.push_back(u);
	was[u] = 2;
 
	for (auto& v : g[u]) {
		if (!was[v]) {
			strongconnect(v);
			lowlink[u] = min(lowlink[v], lowlink[u]);
		}
		else if (was[v] == 2) {
			lowlink[u] = min(lowlink[u], index[v]);
		}
	}
 
	if (lowlink[u] == index[u]) {
		while (true) {
			int w = s.back();
			s.pop_back();
			scc[w] = cur;
			if (w == u) break;
		} 
		cur++;
	}
 
	was[u] = 1;
 
}
 
int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	cin >> n;
	mat.assign(n + 1, bitset<5001>());
	g.resize(2 * n + 1);
	for (int i = 1; i <= n; i++) {
		int k;
		cin >> k;
		while (k--) {
			int a;
			cin >> a;
			mat[a][i] = mat[i][a] = 1;
		}
	}
	for (int i = 1; i <= n - 1; i++) {
		for (int j = i + 1; j <= n; j++) {
			if (mat[i][j]) {
				add_edge(i, j + n);
				add_edge(j, i + n);
			}
			else {
				add_edge(i + n, j);
				add_edge(j + n, i);
			}
		}
	}
 
	was.assign(2 * n + 1, 0);
	scc.assign(2 * n + 1, -1);
 
	index.assign(2 * n + 1, 0);
	lowlink.assign(2 * n + 1, 0);
 
	for (int i = 1; i <= 2 * n; i++) {
		if (!was[i]) {
			strongconnect(i);
		}
	}	
	
	as.resize(n + 1);
	for (int i = 1; i <= n; i++) {
		if (scc[i] == scc[i + n]) {
			cout << 0 << '\n';
			return 0;
		}
		as[i] = scc[i] < scc[i + n];
	}
	int ans = 1;
	int sup = 0, con = 0;
	for (int i = 1; i <= n; i++) {
		sup += 1 - as[i];
		con += as[i];
		x[1 - as[i]].push_back(i);
	}
 
	if ((sup == 0) || (con == 0)) {
		ans = 0;
	}
 
	st.resize(n + 1);
 
	for (auto& u : x[0]) {
		for (auto& v : x[1]) {
			int idx = mat[u][v] ? v : u;
			int idx2 = mat[u][v] ? u : v;
			if (st[idx] > 0) {
				st[idx] = -1;
			} else if (st[idx] == 0) {
				st[idx] = idx2;
			}
		}
	}
 
	for (int i = 1; i <= n; i++) {
		if (st[i] == 0) {
			if ((as[i]) && (con > 1)) ans++;
			if ((!as[i]) && (sup > 1)) ans++;
		}
	}
	
	for (int i = 0; i < 2; i++) {
		for (auto& u : x[i]) {
			if (st[u] == 0) {
				cnt[i][0]++;
			}
			else if (st[u] > 0) {
				cnt[i][1]++;
			}
		}
	}
 
	ans += cnt[0][0] * cnt[1][1] + cnt[0][1] * cnt[1][0];
	
 
 
	cout << ans << '\n';
	return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 10 / 10
• Subtask 10: 10 / 10