Maximize Active Section with Trade I

Description

You are given a binary string s of length n, where:

- '1' represents an active section.

- '0' represents an inactive section.

You can perform at most one trade to maximize the number of active sections in s. In a trade, you:

- Convert a contiguous block of '1's that is surrounded by '0's to all '0's.

- Afterward, convert a contiguous block of '0's that is surrounded by '1's to all '1's.

Return the maximum number of active sections in s after making the optimal trade.

Note: Treat s as if it is augmented with a '1' at both ends, forming t = '1' + s + '1'. The augmented '1's do not contribute to the final count.