Problem

At AcmeCloud, a developer keeps committing API keys to a public repository. You need to build a system that detects exposed secrets and groups nearby exposures into the smallest number of remediation windows.

Given a list of commit timestamps and a list of detected secret exposures, where each exposure has a start_time and end_time, return the minimum number of non-overlapping remediation windows needed after merging all overlapping or adjacent exposure intervals.

Formal Specification

Implement a function that takes exposures, a list of pairs [start_time, end_time], and returns an integer.

• Input: List[List[int]] where each pair represents an inclusive interval.
• Output: int representing the number of merged remediation windows.

Two intervals should be merged if they overlap or if one ends exactly when the next begins.

Examples

Example 1 Input: exposures = [[1, 3], [2, 4], [6, 8]] Output: 2 Explanation: [1, 3] and [2, 4] merge into [1, 4], while [6, 8] remains separate.

Example 2 Input: exposures = [[5, 5], [6, 7], [7, 9]] Output: 1 Explanation: The intervals are adjacent or overlapping, so they merge into one remediation window [5, 9].

Constraints

• 1 <= len(exposures) <= 10^5
• 0 <= start_time <= end_time <= 10^9
• Each exposure is an inclusive interval [start_time, end_time]