Question

How to rearrange an array such that every odd index element is greater than its previous in Java

Answer 1

import java.util.Arrays;

public class MyClass {
    private static void swap(int[] arr, int i, int j) {
    	int temp = arr[i];
    	arr[i] = arr[j];
    	arr[j] = temp;
    }

    private static void rearrangeArray(int[] arr) {
        int size = arr.length;

        for (int i = 0; i < size - 1; i += 2) {
            if (arr[i] > arr[i + 1]) {
                swap(arr, i, i + 1);
            }
        }
     
        // if array size is odd
        if ((size & 1) != 0) {
            for (int i = size - 1; i > 0; i -=2) {
                if (arr[i] > arr[i - 1]) {
                    swap(arr, i, i - 1);
                }
            }
        }
    }
    public static void main(String args[]) {
      	int[] arr = {1, 3, 6, 5, 4, 2, 9, 8, 7};

	    rearrangeArray(arr);

	    System.out.println(Arrays.toString(arr));
    }
}




/*
run:
 
[1, 5, 3, 6, 2, 8, 4, 9, 7]
 
*/

 

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