Given a collection of intervals, find the minimum number of intervals you need to remove to make the rest of the intervals non-overlapping.
Intervals can "touch", such as [0, 1] and [1, 2], but they won't be considered overlapping.
For example, given the intervals (7, 9), (2, 4), (5, 8), return 1 as the last interval can be removed and the first two won't overlap.
The intervals are not necessarily sorted in any order.