quick sort code in java
import java.util.*; class QuickSort { //selects last element as pivot, pi using which array is partitioned. int partition(int intArray[], int low, int high) { int pi = intArray[high]; int i = (low-1); // smaller element index for (int j=low; j<high; j++) { // check if current element is less than or equal to pi if (intArray[j] <= pi) { i++; // swap intArray[i] and intArray[j] int temp = intArray[i]; intArray[i] = intArray[j]; intArray[j] = temp; } } // swap intArray[i+1] and intArray[high] (or pi) int temp = intArray[i+1]; intArray[i+1] = intArray[high]; intArray[high] = temp; return i+1; } //routine to sort the array partitions recursively void quick_sort(int intArray[], int low, int high) { if (low < high) { //partition the array around pi=>partitioning index and return pi int pi = partition(intArray, low, high); // sort each partition recursively quick_sort(intArray, low, pi-1); quick_sort(intArray, pi+1, high); } } } class QUICK_SORT{ public static void main(String args[]) { //initialize a numeric array, intArray int intArray[] = {3,2,1,6,5,4}; int n = intArray.length; //print the original array System.out.println("Original Array: " + Arrays.toString(intArray)); //call quick_sort routine using QuickSort object QuickSort obj = new QuickSort(); obj.quick_sort(intArray, 0, n-1); //print the sorted array System.out.println("\nSorted Array: " + Arrays.toString(intArray)); } }
