#include <vector>
#include <iostream>
#include <set>
#include <bitset>
using namespace std;
int n;
vector< vector<short> > g, tg;
vector< bitset<5001> > mat;
vector<int> was, topoSort, scc;
int cur = 1;
vector<int> as;
vector<int> st;
vector<short> x[2];
int cnt[2][2];
void reverse_graph() {
for (int u = 1; u < 2 * n + 1; u++) {
for (auto& v : g[u]) {
tg[v].push_back(u);
}
vector<short>().swap(g[u]);
}
}
void add_edge(int u, int v) {
g[u].push_back(v);
}
void dfs1(int u) {
was[u] = 1;
for (auto& v : g[u]) {
if (!was[v]) {
dfs1(v);
}
}
topoSort.push_back(u);
}
void dfs2(int u) {
scc[u] = cur;
was[u] = 1;
for (auto& v : tg[u]) {
if (!was[v]) {
dfs2(v);
}
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
cin >> n;
mat.assign(n + 1, bitset<5001>());
g.resize(2 * n + 1);
tg.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);
for (int i = 1; i <= 2 * n; i++) {
if (!was[i]) {
dfs1(i);
}
}
reverse(topoSort.begin(), topoSort.end());
reverse_graph();
scc.assign(2 * n + 1, -1);
was.assign(2 * n + 1, 0);
for (auto& u : topoSort) {
if (!was[u]) {
dfs2(u);
cur++;
}
}
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;
}
Compilation message
kon.cpp: In function 'int main()':
kon.cpp:84:2: error: 'reverse' was not declared in this scope
reverse(topoSort.begin(), topoSort.end());
^~~~~~~
