Question

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

Answer 1

using System;

public class Program
{
	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 = new int[] {1, 3, 6, 5, 4, 2, 9, 8, 7};

		rearrangeArray(arr);

		Console.WriteLine(string.Join(" ", arr));
	}
}




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

 
*/

 

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