Number of Connected Components solution

Author: PDKhan

number-of-connected-components-in-an-undirected-graph/PDKhan.cpp

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+class Solution {
+    public:
+        /**
+         * @param n: the number of vertices
+         * @param edges: the edges of undirected graph
+         * @return: the number of connected components
+         */
+        void dfs(int curr, vector<vector<int>>& graph, vector<bool>& visited){
+            visited[curr] = true;
+    
+            for(int i = 0; i < graph[curr].size(); i++){
+                if(visited[graph[curr][i]] == false)
+                    dfs(graph[curr][i], graph, visited);
+            }
+        }
+    
+        int countComponents(int n, vector<vector<int>> &edges) {
+            // write your code here
+            vector<bool> visited(n, 0);
+            vector<vector<int>> graph (n);
+            int cnt = 0;
+    
+            for(int i = 0; i < edges.size(); i++){
+                graph[edges[i][0]].push_back(edges[i][1]);
+                graph[edges[i][1]].push_back(edges[i][0]);
+            }
+    
+            for(int i = 0; i < n; i++){
+                if(visited[i] == false){
+                    dfs(i, graph, visited);
+                    cnt++;
+                }
+            }
+            
+            return cnt;
+        }
+    };