Remove Covered Intervals

Given a list of intervals, remove all intervals that are covered by another interval in the list. Interval [a,b) is covered by interval [c,d) if and only if c <= a and b <= d.

After doing so, 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.

Constraints:

• 1 <= intervals.length <= 1000

• 0 <= intervals[i][0] < intervals[i][1] <= 10^5

• intervals[i] != intervals[j] for all i != j

class Solution {
    public int removeCoveredIntervals(int[][] intervals) {
        Arrays.sort(intervals, (a, b) -> a[0] == b[0] ? b[1] - a[1] : a[0] - b[0]);
        int count = 0;
        int currentEnd = 0;
        // By sorting we make sure that interval before will definately will have
        // smaller start time therefore we only need to take care of end time
        for (int[] interval : intervals) {
            if (currentEnd < interval[1]) {
                count++;
                currentEnd = interval[1];
            }
        }
        return count;
    }
}