diff --git a/leetcode/BFS.cpp b/leetcode/BFS.cpp
new file mode 100644
index 0000000..c023151
--- /dev/null
+++ b/leetcode/BFS.cpp
@@ -0,0 +1,48 @@
+#include<iostream>
+#include<list>
+using namespace std;
+class Graph{
+	int v;
+	list<int> *adj;
+	public: Graph(int v);
+	void add_edge(int v,int num);
+	void bfs(int source);
+};
+Graph::Graph(int v){
+	this->v=v;
+	adj=new list<int>[v];
+}
+void Graph::add_edge(int v,int num){
+	adj[v].push_back(num);
+}
+void Graph::bfs(int source){
+    bool *visited=new bool[v];
+	for(int i=0;i<v;i++){
+		visited[i]=false;
+	}
+	list<int> queue;
+	visited[source]=true;
+	queue.push_back(source);
+	list<int>::iterator it;
+	while(!queue.empty()){
+		source=queue.front();
+cout<<source<<" ";
+queue.pop_front();
+for(it=adj[source].begin();it!=adj[source].end();++it){
+	if(!visited[*it]){
+		visited[*it]=true;
+		queue.push_back(*it);
+	}
+}
+}
+}
+int main(){
+	Graph g(4);
+	g.add_edge(0, 1);
+	g.add_edge(0, 2);
+  	g.add_edge(1, 2);
+	g.add_edge(2, 0);
+ 	g.add_edge(2, 3);
+   	g.add_edge(3, 3);
+   	g.bfs(2);
+}
\ No newline at end of file
diff --git a/leetcode/DFS.cpp b/leetcode/DFS.cpp
new file mode 100644
index 0000000..ad68596
--- /dev/null
+++ b/leetcode/DFS.cpp
@@ -0,0 +1,43 @@
+#include<iostream>
+#include<list>
+using namespace std;
+class Graph{
+	int n;
+	list<int> *adj;
+	public: Graph(int n);
+	void dfsUtil(int v,bool visited[]);
+	void add_edge(int v,int num);
+	void dfs(int v);
+};
+Graph::Graph(int n){
+	this->n=n;
+	adj=new list<int>[n];
+}
+void Graph::add_edge(int v,int num){
+	adj[v].push_back(num);
+}
+void Graph::dfsUtil(int v,bool visited[]){
+	visited[v]=true;
+	cout<<v<<" ";
+	list<int>::iterator it;
+	for(it=adj[v].begin();it!=adj[v].end();it++)
+		if(!visited[*it])
+			dfsUtil(*it,visited);
+}
+void Graph::dfs(int v){
+	bool *visited=new bool[n];
+	for(int i=0;i<n;i++)
+        visited[i]=false;
+	dfsUtil(v,visited);
+}
+ 
+int main(){
+	Graph g(4);
+	g.add_edge(0, 1);
+g.add_edge(0, 2);
+  	g.add_edge(1, 2);
+g.add_edge(2, 0);
+ 	g.add_edge(2, 3);
+   	g.add_edge(3, 3);
+   	g.dfs(2);
+}
\ No newline at end of file
diff --git a/leetcode/LengthOfSubarrayWithZeroSum.cpp b/leetcode/LengthOfSubarrayWithZeroSum.cpp
new file mode 100644
index 0000000..71889be
--- /dev/null
+++ b/leetcode/LengthOfSubarrayWithZeroSum.cpp
@@ -0,0 +1,44 @@
+#include <bits/stdc++.h> 
+using namespace std; 
+
+// Returns Length of the required subarray 
+int maxLen(int arr[], int n) 
+{ 
+	// Map to store the previous sums 
+	unordered_map<int, int> presum; 
+
+	int sum = 0; // Initialize the sum of elements 
+	int max_len = 0; // Initialize result 
+
+	// Traverse through the given array 
+	for (int i = 0; i < n; i++) { 
+		// Add current element to sum 
+		sum += arr[i]; 
+
+		if (arr[i] == 0 && max_len == 0) 
+			max_len = 1; 
+		if (sum == 0) 
+			max_len = i + 1; 
+
+		// Look for this sum in Hash table 
+		if (presum.find(sum) != presum.end()) { 
+			// If this sum is seen before, then update max_len 
+			max_len = max(max_len, i - presum[sum]); 
+		} 
+		else { 
+			// Else insert this sum with index in hash table 
+			presum[sum] = i; 
+		} 
+	} 
+
+	return max_len; 
+} 
+int main() 
+{ 
+	int arr[] = { 15, -2, 2, -8, 1, 7, 10, 23 }; 
+	int n = sizeof(arr) / sizeof(arr[0]); 
+	cout << "Length of the longest 0 sum subarray is "
+		<< maxLen(arr, n); 
+
+	return 0; 
+}
\ No newline at end of file
diff --git a/leetcode/SortArrayAccToSetBits.cpp b/leetcode/SortArrayAccToSetBits.cpp
new file mode 100644
index 0000000..d336d5c
--- /dev/null
+++ b/leetcode/SortArrayAccToSetBits.cpp
@@ -0,0 +1,38 @@
+#include <bits/stdc++.h> 
+using namespace std; 
+
+void sortArr(int arr[], int n) 
+{ 
+	multimap<int, int> map; 
+
+	for (int i = 0; i < n; i++) { 
+		int count = 0; 
+		int k = arr[i]; 
+
+		// Counting no of setBits in arr[i] 
+		while (k) { 
+			k = k & k - 1; 
+			count++; 
+		} 
+
+		// The count is subtracted from 32 
+		// because the result needs 
+		// to be in descending order 
+		map.insert(make_pair(32 - count, arr[i])); 
+	} 
+
+	// Printing the numbers in descending 
+	// order of set bit count 
+	for (auto it = map.begin(); it != map.end(); it++) { 
+		cout << (*it).second << " "; 
+	} 
+}
+int main() 
+{ 
+	int arr[] = { 5, 2, 3, 9, 4, 6, 7, 15, 32 }; 
+	int n = sizeof(arr) / sizeof(arr[0]); 
+
+	sortArr(arr, n); 
+
+	return 0; 
+} 
\ No newline at end of file
diff --git a/leetcode/dijkstra.cpp b/leetcode/dijkstra.cpp
new file mode 100644
index 0000000..ef8e9f3
--- /dev/null
+++ b/leetcode/dijkstra.cpp
@@ -0,0 +1,46 @@
+#define v 9
+void min_distance(int dist[v],bool trset[v]){
+	int min_dis=INT_MAX, min_index;
+	for(int i=0;i<v;i++){
+		if(dist[i]<=min && sprset[i]==false){
+			min_dis=dist[i];
+			min_index=i;
+		}
+	}
+	return min_index;
+}
+void print_sol(int dis[v]){
+	cout<<”Vertex”<<”\t\tDistance from source”;
+	for(int i=0;i<v;i++)
+		cout<<i<<” “<<dist[i]<<endl;
+}
+void dijkstra(int graph[v][v],int src){
+	int dist[v];
+	bool trset[v];
+	for(int i=0;i<v;i++){
+		dist[v]=INT_MAX;
+		trset[i]=false;
+	}
+	dist[src]=0;
+	for(int i=0;i<v-1;i++){
+		int u=min_distance(dist,trset);
+		trset[u]=true;
+		for(int j=0;j<v;j++){
+			if(!trset[j] && graph[u][j] && dist[u]!=INT_MAX&& dist[u]+graph[u][j]<dist[j])
+				dist[j] = dist[u]+graph[u][j];
+	}
+	print_sol(dist);
+}
+int main(){
+int graph[v][v]={ { 0, 4, 0, 0, 0, 0, 0, 8, 0 }, 
+                        { 4, 0, 8, 0, 0, 0, 0, 11, 0 }, 
+                        { 0, 8, 0, 7, 0, 4, 0, 0, 2 }, 
+                        { 0, 0, 7, 0, 9, 14, 0, 0, 0 }, 
+                        { 0, 0, 0, 9, 0, 10, 0, 0, 0 }, 
+                        { 0, 0, 4, 14, 10, 0, 2, 0, 0 }, 
+                        { 0, 0, 0, 0, 0, 2, 0, 1, 6 }, 
+                        { 8, 11, 0, 0, 0, 0, 1, 0, 7 }, 
+                        { 0, 0, 2, 0, 0, 0, 6, 7, 0 } }; 
+  
+    dijkstra(graph, 0);
+}
\ No newline at end of file