Create Quick Sort.java

programs/Java/Quick Sort.java

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+
+//Sort a given set of n integer elements using Quick Sort method and compute its time complexity.
+
+
+import java.util.Scanner;
+import java.util.Arrays;
+import java.util.Random;
+
+public class QuickSortComplexity
+{
+    static final int MAX = 10005;
+    static int[] a = new int[MAX];
+
+  public static void main(String[] args)
+    {
+        Scanner input = new Scanner(System.in);
+        System.out.print("Enter Max array size: ");
+        long n = input.nextInt();
+        Random random = new Random();
+        System.out.println("Enter the array elements: ");
+        for (int i = 0; i < n; i++)
+        {
+            a[i] = random.nextInt(1000); 
+        }                                         
+        a = Arrays.copyOf(a, n);                           
+        System.out.println("Input Array:");
+        for (int i = 0; i < n; i++)
+            System.out.print(a[i] + " ");
+        long startTime = System.nanoTime();
+        QuickSortAlgo(0, n - 1);
+        long stopTime = System.nanoTime();
+        long elapsedTime = stopTime - startTime;
+        System.out.println("\nSorted Array:");
+        for (int i = 0; i < n; i++)
+            System.out.print(a[i] + " ");
+        System.out.println();
+        System.out.println("Time Complexity in ms for n=" + n + " is: " +
+                           (double)elapsedTime / 1000000);
+    }
+
+  public static void QuickSortAlgo(int f, int l)
+    {
+        int i, j, temp, ele;
+        if (f < l)
+        {
+            i = f;
+            j = l + 1;
+            ele = a[f];
+            while (true)
+            {
+                i++;
+                while (a[i] < ele && i < l)
+                    i++;
+                j--;
+                while (a[j] > ele)
+                    j--;
+                if (i < j)
+                {
+                    temp = a[i];
+                    a[i] = a[j];
+                    a[j] = temp;
+                }
+                else
+                    break;
+            }
+            a[f] = a[j];
+            a[j] = ele;
+            QuickSortAlgo(f, j - 1);
+            QuickSortAlgo(j + 1, l);
+        }
+    }
+}