fn sansa_and_xor(arr: &[i32]) -> i32 {
    //Time complexity: O(n)
    //Space complexity (ignoring input): O(1)
    //A number will appear in {(index+1)*(n-index)} subsequences
    //In case arr.len() is par, the appearences of any number will be par as well
    if arr.len() % 2 == 0 {
        return 0;
    }
    let mut xor_value = 0;
    for index in 0..arr.len() {
        let appearences = (index + 1) * (arr.len() - index);
        if appearences % 2 != 0 {
            xor_value ^= arr[index]
        }
    }
    return xor_value;
}