Swap Odd and Even Bits

Given an u32 return an integer where all the bits in even position are swapped with their adjacent odd bits

The point:

bit in even position swapped with the bit in the next odd position (adjacent)
all bits in even position need to shift by 1 on the left
all bits in odd position need to shift by 1 on the right
use a mask (smoking!) + bitwise-and

Complexity :

Time	Space
O(1)	O(1)

About Rust :

Basic implementation
YES : tested on the Rust Playground

fn swap_odd_and_even_bits(n : u32) -> u32{
    let even_mask = 0x5555_5555;
    let odd_mask = 0xAAAA_AAAA;
    let even_bits = n & even_mask;
    let odd_bits = n & odd_mask;
    // shift the even bit to the lef, the odd bit to the right
    // merge
    (even_bits<<1) | (odd_bits>>1)
}

fn main() { // no main() if this code runs in a Jupyter cell 
    println!("{}", swap_odd_and_even_bits(41)); // 22
    println!("{}", swap_odd_and_even_bits(23)); // 43
} // end of local scope OR end of main()