quick sort algorithm implementation

Author: NirmalSilwal

CodingBlocks Training/Day14/quickSort.java

@@ -0,0 +1,49 @@
+package Lecture14;
+
+public class quickSort {
+
+	public static void main(String[] args) {
+
+		int[] arr = { 7, 2, 1, 6, 8, 5, 3, 4 };
+
+		int start = 0, end = arr.length - 1;
+		quickSorting(arr, start, end);
+		display(arr);
+	}
+
+	public static void quickSorting(int[] arr, int startIndex, int endIndex) {
+		if (startIndex >= endIndex) {
+			return;
+		}
+		int pindex = partition(arr, startIndex, endIndex);
+		quickSorting(arr, startIndex, pindex - 1);
+		quickSorting(arr, pindex + 1, endIndex);
+	}
+
+	public static int partition(int[] arr, int si, int ei) {
+		int pivot = arr[ei];
+		int pindex = si;
+
+		for (int index = si; index <= ei - 1; index++) {
+			if (arr[index] <= pivot) {
+				swap(arr, index, pindex);
+				pindex++;
+			}
+		}
+		swap(arr, pindex, ei);
+		return pindex;
+	}
+
+	public static void swap(int[] arr, int i, int j) {
+		int temp = arr[i];
+		arr[i] = arr[j];
+		arr[j] = temp;
+	}
+
+	public static void display(int[] arr) {
+		for (int index = 0; index < arr.length; index++) {
+			System.out.print(arr[index] + " ");
+		}
+		System.out.println();
+	}
+}