Problem: Given a collection of intervals, write a function that returns the total non-overlapping range covered.
Input: [(0, 15), (11, 17), (10, 20), (45, 50)]
Output: [(0, 20), (45, 50)]
Visualization
(0,15) ---------------
(11,17) -------
(10,20) -------------------
(45,50) -----
result ---------------------------- -----
0
