Find gaps between intervals

You are given a list of integer intervals `intervals`, where each interval is represented as `[start, end]` (inclusive), and `start <= end`. Two intervals may overlap or touch (e.g., `[1,3]` and `[4,6]` touch if you consider integers, because there is no missing integer between 3 and 4). Your task is to find **all gaps** (missing ranges) **between** the covered portions of the number line. More precisely: 1. Consider the union of all intervals. 2. Let `minCovered` be the smallest integer covered by any interval, and `maxCovered` be the largest integer covered by any interval. 3. Return a list of **all maximal missing integer ranges** within `[minCovered, maxCovered]` that are **not covered** by the union. Return the gaps as a list of disjoint intervals `[gapStart, gapEnd]` (inclusive), sorted by `gapStart`. ### Example - Input: `[[1,3],[7,10],[2,4]]` - Covered union is `[1,4] ∪ [7,10]` - Gaps within `[1,10]` are `[[5,6]]` - Output: `[[5,6]]` ### Notes / Edge cases - If the union is already contiguous (no gaps), return `[]`. - Overlapping intervals should not create gaps. - Intervals may be unsorted. ### Constraints (reasonable interview assumptions) - `1 <= len(intervals) <= 2e5` - Interval endpoints fit in 32-bit signed integers.