quick sort algorithm added

DSA/Sorting Algorithm/Java/QuickSort.java

@@ -0,0 +1,37 @@
+//T(n): O(n*n)
+//S(n): O(1)
+public class Main
+{
+    public static void swap(int[] arr, int i, int j) {
+        int temp = arr[i];
+        arr[i] = arr[j];
+        arr[j] = temp;
+    }
+    public static int partition(int[] arr, int low, int high) {
+        int pivot = high;
+        int i = low - 1;
+        //if any value is less than pivot, area 1 should occupy lesser elements
+        for (int j = low; j <= high - 1; j++) {
+            if (arr[j] < arr[pivot]) {
+                i++;
+                swap(arr, i, j);
+            }
+        }
+        swap(arr, i + 1, pivot);
+        return i + 1;
+    }
+    public static void QuickSort(int[] arr, int low, int high) {
+        if (low < high) {
+            int p = partition(arr, low, high);
+            QuickSort(arr, low, p - 1);
+            QuickSort(arr, p + 1, high);
+        }
+    }
+	public static void main(String[] args) {
+	    int[] arr = {9, 8, 7, 5, 2, 1};
+	    QuickSort(arr, 0, 5);
+	    for (int i: arr) {
+	    System.out.print(i +" ");
+	    }
+	}
+}