Given an array intervals where intervals[i] = [li, ri] represent the interval [li, ri), remove all intervals that are covered by another interval in the list.
The interval [a, b) is covered by the interval [c, d) if and only if c <= a and b <= d.
Return the number of remaining intervals.
Example 1:
Input: intervals = [[1,4],[3,6],[2,8]]
Output: 2
Explanation: Interval [3,6] is covered by [2,8], therefore it is removed.
Example 2:
Input: intervals = [[1,4],[2,3]]
Output: 1
Solution
class Solution:
def removeCoveredIntervals(self, intervals: List[List[int]]) -> int:
intervals = sorted(intervals, key=lambda x: (x[0], -x[1]))
out = 0
end = 0
for _, e in intervals:
if e > end:
out += 1
end = e
return out