0
1
mirror of https://git.sb/baoshuo/OI-codes.git synced 2024-12-25 17:52:02 +00:00
OI-codes/Luogu/P2812/P2812.cpp
2022-01-02 19:10:52 +08:00

71 lines
1.4 KiB
C++

#include <iostream>
#include <stack>
#include <vector>
using std::cin;
using std::cout;
using std::endl;
const int N = 100005;
int n, x, ans1, ans2;
std::vector<int> g[N];
// Tarjan
int cnt, dfn[N], low[N];
int scc_cnt, id[N];
std::stack<int> st;
bool vis[N];
int din[N], dout[N];
void tarjan(int u) {
dfn[u] = low[u] = ++cnt;
st.push(u);
vis[u] = true;
for (int v : g[u]) {
if (!dfn[v]) {
tarjan(v);
low[u] = std::min(low[u], low[v]);
} else if (vis[v]) {
low[u] = std::min(low[u], dfn[v]);
}
}
if (low[u] == dfn[u]) {
scc_cnt++;
int v;
do {
v = st.top();
st.pop();
vis[v] = false;
id[v] = scc_cnt;
} while (v != u);
}
}
int main() {
cin >> n;
for (int i = 1; i <= n; i++) {
while (cin >> x, x) {
g[i].push_back(x);
}
}
for (int i = 1; i <= n; i++) {
if (!dfn[i]) tarjan(i);
}
for (int i = 1; i <= n; i++) {
for (int v : g[i]) {
if (id[i] != id[v]) {
din[id[v]]++;
dout[id[i]]++;
}
}
}
for (int i = 1; i <= scc_cnt; i++) {
ans1 += !din[i];
ans2 += !dout[i];
}
cout << ans1 << endl
<< (scc_cnt == 1 ? 0 : std::max(ans1, ans2)) << endl;
return 0;
}