11266 cut vertex

baekjoon/11266_cutVertex.cpp

@@ -0,0 +1,88 @@
+#include <iostream>
+#include <vector>
+#include <set>
+#include <algorithm>
+
+using namespace std;
+
+#define INF 1234567890
+
+int V, E;
+vector<vector<int>> graph;
+vector<int> v_order;
+vector<bool> v_visit;
+set<int> set_cutVertex;
+
+int DFS(int current, int order)
+{
+    v_visit[current] = true;
+    v_order[current] = order;
+    int fastParent = current;
+    for (auto next : graph[current])
+    {
+        if (v_order[next] < v_order[fastParent])
+            fastParent = next;
+        if (!v_visit[next])
+        {
+            int result = DFS(next, order + 1);
+            if (result == current)
+                set_cutVertex.insert(current);
+            if (v_order[result] < v_order[fastParent])
+                fastParent = result;
+        }
+    }
+    return fastParent;
+}
+
+void findCutVertex()
+{
+    for (int i = 1; i <= V; i++)
+    {
+        if (v_visit[i])
+            continue;
+        int root = i;
+        int order = 1;
+        v_visit[root] = true;
+        v_order[root] = order;
+
+        int visitCount = 0;
+        for (auto next : graph[root])
+        {
+            if (!v_visit[next])
+            {
+                visitCount++;
+                int result = DFS(next, order + 1);
+            }
+        }
+        if (visitCount >= 2)
+            set_cutVertex.insert(root);
+    }
+}
+
+void solution()
+{
+    cin >> V >> E;
+    graph.resize(V + 1);
+    v_order.resize(V + 1, INF);
+    v_visit.resize(V + 1, false);
+    for (int i = 1; i <= E; i++)
+    {
+        int node1, node2;
+        cin >> node1 >> node2;
+        graph[node1].push_back(node2);
+        graph[node2].push_back(node1);
+    }
+
+    findCutVertex();
+    cout << set_cutVertex.size() << "\n";
+    for (auto cutVertex : set_cutVertex)
+        cout << cutVertex << " ";
+}
+
+int main()
+{
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+    solution();
+    return 0;
+}