Update

C++/Cycle Detection in Directed Graph.cpp

@@ -0,0 +1,71 @@
+#include <bits/stdc++.h>
+using namespace std;
+#define ll long long
+#define mod 1000000007
+#define mod9 998244353
+#define raftaar                       \
+    ios_base::sync_with_stdio(false); \
+    cin.tie(NULL);                    \
+    cout.tie(NULL)
+#define endl "\n"
+bool dfs(int node, vector<int> adj[], vector<bool> &vis, vector<int> &check)
+{
+    vis[node] = 1;
+    check[node] = 1;
+    for (auto x : adj[node])
+    {
+        if (!vis[x])
+        {
+            if (dfs(x, adj, vis, check))
+            {
+                return true;
+            }
+        }
+        if (check[x])
+        {
+            return true;
+        }
+    }
+    check[node] = 0;
+    return false;
+}
+bool isCyclic(int V, vector<int> adj[])
+{
+    vector<bool> vis(V, 0);
+    vector<int> check(V, 0);
+
+    for (int i = 0; i < V; i++)
+    {
+        if (!vis[i])
+        {
+            if (dfs(i, adj, vis, check))
+            {
+                return true;
+            }
+        }
+    }
+
+    return false;
+}
+int main()
+{
+    raftaar;
+    int node, edges;
+    cin >> node >> edges;
+    vector<int> adj[node];
+    for (int i = 0; i < edges; i++)
+    {
+        int u, v;
+        cin >> u >> v;
+        adj[u].push_back(v);
+    }
+    bool ans = isCyclic(node, adj);
+    if (ans)
+    {
+        cout << "The Graph contain cycle" << endl;
+    }
+    else
+    {
+        cout << "The Graph does not contain cycle" << endl;
+    }
+}

Java/Program 21/Quick_Sort.java

@@ -0,0 +1,79 @@
+import java.util.Arrays;
+
+public class QuickSortDemo{
+
+    public static void main(String args[]) {
+
+        // unsorted integer array
+        int[] unsorted = {6, 5, 3, 1, 8, 7, 2, 4};
+        System.out.println("Unsorted array :" + Arrays.toString(unsorted));
+
+        QuickSort algorithm = new QuickSort();
+
+        // sorting integer array using quicksort algorithm
+        algorithm.sort(unsorted);
+
+        // printing sorted array
+        System.out.println("Sorted array :" + Arrays.toString(unsorted));
+
+    }
+
+}
+
+class QuickSort {
+
+    private int input[];
+    private int length;
+
+    public void sort(int[] numbers) {
+
+        if (numbers == null || numbers.length == 0) {
+            return;
+        }
+        this.input = numbers;
+        length = numbers.length;
+        quickSort(0, length - 1);
+    }
+
+    /*
+     * This method implements in-place quicksort algorithm recursively.
+     */
+    private void quickSort(int low, int high) {
+        int i = low;
+        int j = high;
+
+        // pivot is middle index
+        int pivot = input[low + (high - low) / 2];
+
+        // Divide into two arrays
+        while (i <= j) {
+            while (input[i] < pivot) {
+                i++;
+            }
+            while (input[j] > pivot) {
+                j--;
+            }
+            if (i <= j) {
+                swap(i, j);
+                // move index to next position on both sides
+                i++;
+                j--;
+            }
+        }
+
+        // calls quickSort() method recursively
+        if (low < j) {
+            quickSort(low, j);
+        }
+
+        if (i < high) {
+            quickSort(i, high);
+        }
+    }
+
+    private void swap(int i, int j) {
+        int temp = input[i];
+        input[i] = input[j];
+        input[j] = temp;
+    }
+}

Java/Readme.md

@@ -24,6 +24,8 @@
 | [Program-18](https://github.com/swaaz/basicprograms/blob/814a1e60ae23d81158d8174666f23c9b7419e15e/Java/Program-18/Program%20Number%20to%20Word.java) | Program to calculate electricity bill
 | [Program-19](https://github.com/swaaz/basicprograms/blob/814a1e60ae23d81158d8174666f23c9b7419e15e/Java/Program-19/Program%20Number%20to%20Word.java) | Program to calculate discount
 | [Program-20](https://github.com/swaaz/basicprograms/blob/814a1e60ae23d81158d8174666f23c9b7419e15e/Java/Program-20/Program%20Number%20to%20Word.java) | Program to calculate batting average
+| [Program-21]() | Quicksort Sorting Algorithm in java.  
+
 
  </div>