Add QuickSort in Java Language

Author: Abhay Maniyar

Searching and Sorting/Quick Sort/Java/QuickSort.java

@@ -0,0 +1,69 @@
+// Java program for implementation of QuickSort 
+class QuickSort {
+    /*
+     * This function takes last element as pivot, places the pivot element at its
+     * correct position in sorted array, and places all smaller (smaller than pivot)
+     * to left of pivot and all greater elements to right of pivot
+     */
+    int partition(int arr[], int low, int high) {
+        int pivot = arr[high];
+        int i = (low - 1); // index of smaller element
+        for (int j = low; j < high; j++) {
+            // If current element is smaller than the pivot
+            if (arr[j] < pivot) {
+                i++;
+
+                // swap arr[i] and arr[j]
+                int temp = arr[i];
+                arr[i] = arr[j];
+                arr[j] = temp;
+            }
+        }
+
+        // swap arr[i+1] and arr[high] (or pivot)
+        int temp = arr[i + 1];
+        arr[i + 1] = arr[high];
+        arr[high] = temp;
+
+        return i + 1;
+    }
+
+    /*
+     * The main function that implements QuickSort() arr[] --> Array to be sorted,
+     * low --> Starting index, high --> Ending index
+     */
+    void sort(int arr[], int low, int high) {
+        if (low < high) {
+            /*
+             * pi is partitioning index, arr[pi] is now at right place
+             */
+            int pi = partition(arr, low, high);
+
+            // Recursively sort elements before
+            // partition and after partition
+            sort(arr, low, pi - 1);
+            sort(arr, pi + 1, high);
+        }
+    }
+
+    /* A utility function to print array of size n */
+    static void printArray(int arr[]) {
+        int n = arr.length;
+        for (int i = 0; i < n; ++i)
+            System.out.print(arr[i] + " ");
+        System.out.println();
+    }
+
+    // Driver program
+    public static void main(String args[]) {
+        int arr[] = { 10, 7, 8, 9, 1, 5 };
+        int n = arr.length;
+
+        QuickSort ob = new QuickSort();
+        ob.sort(arr, 0, n - 1);
+
+        System.out.println("sorted array");
+        printArray(arr);
+    }
+}
+/* This code is contributed by Rajat Mishra */