Function to rearrange array elements such that the every two consecutive elements is a multiple of 4
public static void Permute ( List < int > arr , int n ) { int odd = 0 , four = 0 ; int non_four = 0 ; List < int > ODD = new List < int > ( ) ; List < int > FOUR = new List < int > ( n ) ; List < int > NON_FOUR = new List < int > ( n ) ; foreach ( int x in arr ) {