Added cycle_detect.cpp

graphs/count_diconnected_components.cpp

@@ -0,0 +1,69 @@
+#include<iostream> 
+#include<list> 
+using namespace std; 
+
+int count=1;
+// Graph class represents a directed graph 
+// using adjacency list representation 
+class Graph 
+{ 
+    int V;
+    list<int> *adj; 
+    void DFSUtil(int v, bool visited[]); 
+public: 
+    Graph(int V); 
+    void addEdge(int v, int w);  
+    void DFS(int v); 
+}; 
+
+Graph::Graph(int V) 
+{ 
+    this->V = V; 
+    adj = new list<int>[V]; 
+} 
+
+void Graph::addEdge(int v, int w) 
+{ 
+    adj[v].push_back(w); // Add w to v’s list. 
+} 
+
+void Graph::DFSUtil(int v, bool visited[]) 
+{ 
+    visited[v] = true;
+    list<int>::iterator i; 
+    for (i = adj[v].begin(); i != adj[v].end(); ++i) 
+        if (!visited[*i]) 
+            DFSUtil(*i, visited); 
+} 
+void Graph::DFS(int v) 
+{  
+    bool *visited = new bool[V]; 
+    for (int i = 0; i < V; i++) 
+        visited[i] = false;
+    DFSUtil(v, visited);
+    for (int i = 0; i < V; i++) 
+        if(visited[i] == false)
+        {
+            count++;
+            DFSUtil(i, visited);
+        }
+} 
+
+int main() 
+{ 
+    Graph g(9); 
+    g.addEdge(0, 1); 
+    g.addEdge(0, 2); 
+    g.addEdge(1, 2); 
+    g.addEdge(2, 0); 
+    g.addEdge(2, 3); 
+    g.addEdge(3, 3);
+    g.addEdge(4, 5);
+    g.addEdge(6, 7);
+    g.addEdge(6, 8);
+
+    g.DFS(2);
+    cout << "Number of disconnected components in the given graph is : " <<count;; 
+
+    return 0; 
+}

graphs/cycle_detect.cpp

@@ -0,0 +1,51 @@
+//cycle detection in graph implemented in C++
+//Author : Rituparno Biswas
+
+
+#include<bits/stdc++.h>
+using namespace std;
+
+typedef long long int ll;
+
+int check=0;
+int visited[1000]={0};
+vector<int > v[1000];
+
+void dfs(int curr , int p)
+{
+	visited[curr]=1;
+	for(auto i:v[curr])
+	{
+		if(visited[i]==1)
+		{
+			if(i!=p)
+				check=1;
+		}
+		else
+		{
+			dfs(i, curr);
+		}
+	}
+}
+
+
+void addEdge(int a, int b) 
+{ 
+    v[a].push_back(b); // Add w to v’s list. 
+    v[b].push_back(a); // Add v to w’s list. 
+} 
+
+int main() 
+{ 
+	addEdge(1, 0); 
+    addEdge(0, 2);  
+    addEdge(1, 2); 
+    addEdge(0, 3); 
+    addEdge(3, 4); 
+    dfs(0,-1);
+    if(check)
+    	cout<<"Cycle present";
+    else
+    	cout<<"Cycle not present";
+	return 0; 
+} 

sorting/selection_sort.cpp

@@ -0,0 +1,49 @@
+// C++ implementation of selection sort
+//
+// Author: Rituparno Biswas
+
+#include <iostream>
+
+// Swap elements
+void swap(int *x, int *y)
+{
+	int temp = *x;
+	*x = *y;
+	*y = temp;
+}
+
+// Implement selection sort
+void selectionSort(int arr[], int n)
+{
+   int i, j, min_id;
+   for (i = 0; i < n-1; i++)
+   {
+   		min_id=i;
+   		for (j = i+1; j < n; j++)
+   			if (arr[min_id] > arr[j])
+   				min_id=j;
+   			swap(&arr[i], &arr[min_id]);
+   	}
+}
+
+// Function to print elements
+void printArray(int arr[], int size)
+{
+	int i;
+	for (i=0; i < size; i++)
+		printf("%d ", arr[i]);
+	printf("\n");
+}
+
+// test
+int main()
+{
+	int arr[] = {46, 24, 33, 10, 2, 81, 50};
+	int n = sizeof(arr)/sizeof(arr[0]);
+	printf("Unsorted array: \n");
+	printArray(arr, n);
+	selectionSort(arr, n);
+  	printf("Sorted array: \n");
+	printArray(arr, n);
+  return 0;
+}