Your right, the authorized shares are 450,000,000. That is the total amount of shares the company is authorized to use. It doesn't matter if they are currently in use or not, that is just the total amount available.
The outstanding shares are those that are currently in use, in in one way or another. So, if 450,000,000 is authorized and from those 381,623,575 are outstanding, then 68,376,425 (A/S - O/S) is still in the treasury. Meaning the unused shares that the company can still do with as they see fit.
Now, the O/S is the sum of the float and restricted shares. These are the shares that are NOT in the treasury and are in the market. Of course, the restricted shares are in the market, but not tradable. The float are also in the market, but are tradable.
So, we know the O/S is 381,623,575. We also know the total restricted shares are 138,847,663. So, knowing the the O/S = restricted + float, then subtract the restricted from the total O/S and you get the float.