ShuffleInteger.rb

# Shuffle integers
# Given an array arr[] of n elements in the following format {a1, a2, a3, a4, .., an/2, b1, b2, b3, b4, ., bn/2}, the task is shuffle the array to {a1, b1, a2, b2, a3, b3, , an/2, bn/2} without using extra space.
# Example 1:
# 		Input: n = 4, arr[] = {1, 2, 9, 15}
# 		Output:  1 9 2 15
# 		Explanation: a1=1 , a2=2 , b1=9 , b2=15
# 		So the final array will be :  
# 		a1, b1, a2, b2 = { 1, 9, 2, 15 }

# Example 2:
# 		Input: n = 6
# 		arr[] = {1, 2, 3, 4, 5, 6}
# 		Output: 1 4 2 5 3 6
# Your Task:
# This is a function problem. 
# You don't need to take any input, as it is already accomplished by the driver code. 
# You just need to complete the function shuffleArray() that takes array arr[], and an integer n as parameters and modifies the given array according to the above-given pattern.
#
# Expected Time Complexity: O(n).
# Expected Auxiliary Space: O(1).

#---------------
# Naive solution
def shuffleIntegers(arr, n)
	dc = nil
	ac = []
	
	#-------------------------------------------------------------
	# Divide it by 2 - ruby by default it will consider as integer
	dc = (n/2)
	dc.times { |index| ac << arr[index] << arr[-dc + index] }
	return ac
end

arr = [1, 2, 3, 4, 5, 6]
n = 6
p shuffleIntegers(arr, n)