package Sorts;

import java.util.Random;

// https://en.wikipedia.org/wiki/Odd%E2%80%93even_sort

public class OddEvenSort {

public static void main(String[] args) {

int[] arr = new int[100];

Random random = new Random();

// Print out unsorted elements

for (int i = 0; i < arr.length; ++i) {

arr[i] = random.nextInt(100) - 50;

System.out.println(arr[i]);

}

System.out.println("--------------");

oddEvenSort(arr);

//Print Sorted elements

for (int i = 0; i < arr.length - 1; ++i) {

System.out.println(arr[i]);

assert arr[i] <= arr[i + 1];

}

}

/**

* Odd Even Sort algorithms implements

*

* @param arr the array contains elements

*/

public static void oddEvenSort(int[] arr) {

boolean sorted = false;

while(!sorted) {

sorted = true;

for(int i = 1; i < arr.length-1; i += 2){

if (arr[i] > arr [i + 1]){

swap(arr, i, i+1);

sorted = false;

}

}

for (int i = 0; i < arr.length - 1; i+= 2){

if( arr[i] > arr[i + 1] ){

swap(arr, i, i+1);

sorted = false;

}

}

}

}

/**

* Helper function to swap two array values.

*

* @param arr the array contains elements

* @param i the first index to be swapped

* @param j the second index to be swapped

*/

private static void swap(int[] arr, int i, int j) {

int temp = arr[i];

arr[i] = arr[j];

arr[j] = temp;

}

}