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