mirror of
https://git.sb/baoshuo/OI-codes.git
synced 2024-11-05 15:18:47 +00:00
63 lines
1.2 KiB
C++
63 lines
1.2 KiB
C++
#include <array>
|
|
#include <iostream>
|
|
#include <stack>
|
|
#include <vector>
|
|
|
|
using std::cin;
|
|
using std::cout;
|
|
using std::endl;
|
|
|
|
const int N = 10005;
|
|
|
|
int ans;
|
|
std::array<std::vector<int>, N> g;
|
|
|
|
// Tarjan
|
|
int root;
|
|
std::array<int, N> dfn;
|
|
int cnt, low[N];
|
|
int dcc_cnt, id[N];
|
|
std::stack<int> st;
|
|
|
|
void tarjan(int);
|
|
|
|
int main() {
|
|
int n, m;
|
|
while (cin >> n >> m, n || m) {
|
|
ans = dcc_cnt = cnt = 0;
|
|
dfn.fill(0);
|
|
g.fill({});
|
|
for (int i = 1; i <= m; i++) {
|
|
int a, b;
|
|
cin >> a >> b;
|
|
g[a + 1].push_back(b + 1);
|
|
g[b + 1].push_back(a + 1);
|
|
}
|
|
for (int i = 1; i <= n; i++) {
|
|
if (!dfn[i]) {
|
|
root = i;
|
|
dcc_cnt++;
|
|
tarjan(i);
|
|
}
|
|
}
|
|
cout << ans + dcc_cnt - 1 << endl;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
void tarjan(int u) {
|
|
dfn[u] = low[u] = ++cnt;
|
|
int size = 0;
|
|
for (int v : g[u]) {
|
|
if (!dfn[v]) {
|
|
tarjan(v);
|
|
low[u] = std::min(low[u], low[v]);
|
|
if (low[v] >= dfn[u]) size++;
|
|
} else {
|
|
low[u] = std::min(low[u], dfn[v]);
|
|
}
|
|
}
|
|
if (u != root) size++;
|
|
ans = std::max(ans, size);
|
|
}
|