Quick Sort

Author: jimmy17x

bin/sortingNSearching/QuickSort.class

@@ -0,0 +1,64 @@
+package sortingNSearching;
+
+public class QuickSort {
+	public static void main(String[] args) {
+		int num[] = new int[10];
+		for (int i = 0; i < num.length; ++i) {
+			num[i] = (int) (Math.random() * 100);
+		}
+
+		// before sort
+		System.out.println("Before sort : ");
+		for (int i = 0; i < num.length; ++i)
+			System.out.print(num[i] + " ");
+
+		System.out.println("\n after sort : ");
+
+		int helper[] = new int[num.length];
+
+		quickSort(num, 0, num.length - 1);
+
+	
+		
+		for (int i = 0; i < num.length; ++i)
+			System.out.print(num[i] + " ");
+
+	}
+
+	private static void quickSort(int[] num, int low, int high) {
+		if (low < high) {
+			int index = partition(num, low, high);
+			if (low < index - 1)
+				quickSort(num, low, index - 1);// sort left half
+			if (index < high)
+				quickSort(num, index, high);// sort right half
+		}
+
+	}
+
+	private static int partition(int[] num, int low, int high) {
+		int pivot = num[low + (high - low) / 2];
+		while (low <= high) {
+			// find first element from left which should be on right
+			while (num[low] < pivot)
+				++low;
+
+			// find first element from right which should be on left
+			while (num[high] > pivot)
+				--high;
+
+			// swap elements and move left and right indices
+			if (low <= high) {
+				int temp = num[high];
+				num[high] = num[low];
+				num[low] = temp;
+				++low;
+				--high;
+
+			}
+
+		}
+		return low;
+	}
+
+}