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 = 1; i < size; i += 2) {
// previous element is greater than current element
if (arr[i - 1] > arr[i]) {
swap(arr, i - 1, i);
}
// next element is greater than current element
if (i + 1 < size && arr[i + 1] > arr[i]) {
swap(arr, i + 1, i);
}
}
}
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 6 3 5 2 9 4 8 7
*/
