Given a list of offsets, ordered by when they are processed, return a list of offsets that represent the greediest order of commits.
That is, when an offset CAN be committed, we MUST commit it.

We can commit an offset X when EITHER:

X = 0, since it is the first message of the stream
All offsets < X are either ready to be committed or are already committed
If we cannot commit offset X, we represent this as -1.

Example 1:
Input: [2, 0, 1]
Output: [-1, 0, 2]

Example 2:
Input: [0, 1, 2]
Output: [0, 1, 2]

Example 3:
Input: [2, 1, 0, 5, 4]
Output: [-1, -1, 2, -1, -1]

We never have duplicate offsets.

Follow-up do it in O(n) time and O(1) space complexity