Merge pull request #159 from navaneet625/main

strongly connected component graph

strongly_connected_component.cpp

@@ -0,0 +1,64 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+void dfs(vector<vector<int>>&adj, vector<bool>&vis, int node, vector<int>&st)
+{
+	vis[node] = true;
+	for (auto nbr : adj[node])
+	{
+		if (!vis[nbr])
+			dfs(adj, vis, nbr, st);
+	}
+	st.push_back(node);
+}
+
+void dfs_(vector<vector<int>>&adj, vector<bool>&vis, int node)
+{
+	vis[node] = true;
+	cout << node << " ";
+	for (auto nbr : adj[node])
+	{
+		if (!vis[nbr])
+			dfs_(adj, vis, nbr);
+	}
+}
+
+int main()
+{
+	int n, m;
+	cin >> n >> m;
+
+	vector<vector<int>> adj(n), rev_adj(n);
+	while (m--)
+	{
+		int a, b;
+		cin >> a >> b;
+		adj[a].push_back(b);
+		rev_adj[b].push_back(a);
+	}
+	vector<bool>vis(n, false);
+	vector<int>st;//use stack
+
+	for (int i = 0; i < n; i++)
+	{
+		if (!vis[i])
+			dfs(adj, vis, i, st);
+	}
+	fill(vis.begin(), vis.end(), false);
+
+
+	char comp_name = 'A';
+
+	for (int i = st.size() - 1; i >= 0; i--)
+	{
+		int node = st[i];
+		if (!vis[node])
+		{
+			cout << "component " << comp_name << "-->";
+			dfs_(rev_adj, vis, node);
+			cout << endl;
+			comp_name++;
+		}
+	}
+
+}