Definition
range: an integer range denoted by [a, b], with a and b both included.
Challenge
Given a list/array of even length, whose each pair of number is representing a range, return a sorted list of ranges in the same format, with all overlapping or contiguous ranges merged.
Examples
actual input: [1, 3, 2, 4, 7, 9] | [7, 10, 3, 5, 2, 4]
equivalent input ranges: [[1, 3], [2, 4], [7, 9]] | [[7, 10], [3, 5], [2, 4]]
actual output: [1, 4, 7, 9] | [2, 5, 7, 10]
equivalent output ranges: [[1, 4], [7, 9]] | [[2, 5], [7, 10]]
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actual input: [] | [0, 0, 1, 1, 2, 2]
equivalent input ranges: [] | [[0, 0], [1, 1], [2, 2]]
actual output: [] | [0, 2]
equivalent output ranges: [] | [[0, 2]]