def larrysArray(a)
    a_sorted = a.sort
    (a.length-2).times do |i|
        index = a.find_index(i+1)
        if (index - i) % 2 == 0
            a.insert(i, a.delete_at(index))   
        else
            a.insert(i,a.delete_at(index))
            a[i+1], a[i+2] = a[i+2], a[i+1]
        end            
    end
    return "YES" if a == a_sorted
    return "NO"
end