A Boolean Array Puzzle

Input: A array arr[] of two elements having value 0 and 1
Output: Make both elements 0. 

Specifications: Following are the specifications to follow.

1) It is guaranteed that one element is 0 but we do not know its position.
2) We can't say about another element it can be 0 or 1.
3) We can only complement array elements, no other operation like and, or, multi, division, .... etc.
4) We can't use if, else and loop constructs.
5) Obviously, we can't directly assign 0 to array elements.

There are several ways we can do it as we are sure that always one Zero is there. Thanks to devendraiiit for suggesting following 3 methods.

Method 1

Time Complexity: O(1)

Auxiliary Space: O(1)

Method 2

Time Complexity: O(1)

Auxiliary Space: O(1)

Method 3
This method doesn't even need complement. 

Time Complexity: O(1)

Auxiliary Space: O(1) 

Method 4
Thanks to purvi for suggesting this method.

Time Complexity: O(1)

Auxiliary Space: O(1)

There may be many more methods.
Please write comments if you find the above codes incorrect, or find other ways to solve the same problem.