mirror of
https://gitcode.com/Zengtudor/alg2025.git
synced 2025-10-20 06:52:28 +00:00
72 lines
1.5 KiB
C++
72 lines
1.5 KiB
C++
#include <algorithm>
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#include <iostream>
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#include <vector>
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const int MAXN = 2e4 + 5;
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int n, m;
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std::vector<int> adj[MAXN];
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int dfn[MAXN], low[MAXN], ts;
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bool is_cut[MAXN];
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std::vector<int> cut_points;
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void tarjan(int u, int parent) {
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dfn[u] = low[u] = ++ts;
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int child_count = 0;
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for (int v : adj[u]) {
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if (v == parent) {
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continue;
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}
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if (!dfn[v]) {
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child_count++;
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tarjan(v, u);
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low[u] = std::min(low[u], low[v]);
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if (parent != 0 && low[v] >= dfn[u]) {
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is_cut[u] = true;
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}
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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 (parent == 0 && child_count > 1) {
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is_cut[u] = true;
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}
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}
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int main() {
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std::ios_base::sync_with_stdio(false);
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std::cin.tie(nullptr);
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std::cin >> n >> m;
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for (int i = 0; i < m; ++i) {
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int u, v;
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std::cin >> u >> v;
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if (u == v) continue;
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adj[u].push_back(v);
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adj[v].push_back(u);
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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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tarjan(i, 0);
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}
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}
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int count = 0;
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for (int i = 1; i <= n; ++i) {
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if (is_cut[i]) {
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count++;
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}
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}
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std::cout << count << "\n";
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bool first = true;
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for (int i = 1; i <= n; ++i) {
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if (is_cut[i]) {
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if (!first) {
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std::cout << " ";
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}
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std::cout << i;
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first = false;
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}
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}
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std::cout << "\n";
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}//TODO REBUILD
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