Implement a program to find the common elements in two arrays without using any extra data structures.

Here ' s one way to implement a program to find the common elements in two arrays without using any extra data structures : \n ``` \n def common _ elements ( arr 1 , arr 2 ): \n # Check if the length of the arrays are the same \n if len ( arr 1 ) != len ( arr 2 ): \n return [] \n \n # Create a set to store the common elements \n common _ elements = set () \n \n # Iter ate through the arrays and add the elements to the set \n for i in range ( len ( arr 1 )): \n if arr 1 [ i ] in arr 2 : \n common _ elements . add ( arr 1 [ i ]) \n \n # Return the common elements \n return common _ elements \n ``` \n This function takes in two arrays , ` arr 1 ` and ` arr 2 `, and returns a set of the common elements between the two arrays . It first checks if the length of the arrays are the same , and if not , it returns an empty set . If the lengths are the same , it creates a set called ` common _ elements ` and iter ates through the arrays , adding any elements that are in both arrays to the set . Finally , it returns the set of common elements . \n \n Here ' s an example of how you could use this function : \n ``` \n arr 1 = [ 1 , 2 , 3 , 4 , 5 ] \n arr 2 = [ 2 , 3 , 4 , 5 , 6 ] \n \n common _ elements = common _ elements ( arr 1 , arr 2 ) \n print ( common _ elements ) # Output : { 2 , 3 , 4 , 5 } \n ``` \n In this example , the common elements between ` arr 1 ` and ` arr 2 ` are `[ 2 , 3 , 4 , 5 ]`. </s>