Maximum xor with Min X

Problem Description

Given an integer A, select two integers (X, Y) such that 1 <= X, Y <= A, such that they have maximum possible xor.

If there are multiple (X, Y); choose one with the smallest X.

Problem Constraints

1 <= A <= 210⁹

Input Format
First argument contains a single integer A.

Output Format
Return a integer array of size 2 of the form [X, Y]

Example Input
Input 1:

A = 1

Input 2:

A = 2

Example Output
Output 1:

[1, 1]

Output 2:

[1, 2]

Example Explanation*

Explanation 1:

    there is only one possible pair to choose, (1,1)

Explanation 2:

    There are four options: (1,1), (1,2), (2,1), (2,2). (1,1) and (2,2) have xor 0 whereas (1,2) and (2,1) have xor 3.
    We chose (1,2) since it has smaller x.

NOTE: You only need to implement the given function. Do not read input, instead use the arguments to the function. Do not print the output, instead return values as specified. Still have a question? Checkout Sample Codes for more details.

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Maximum xor with Min X

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