[LeetCode] 1288. Remove Covered Intervals

 Problem : https://leetcode.com/problems/remove-covered-intervals/

Steps:

- Sort intervals by its beginning point in ascending order. If beginning point are the same, sort by ending point in descending order.

- Iterate all intervals.  If one interval cannot extend current ending point to further position, then it is covered and can be removed.

Time complexity = O ( N * Log(N) ) + O ( N )

class Solution {
    public int removeCoveredIntervals(int[][] intervals) {
        Arrays.sort(intervals, (a, b) -> a[0] != b[0] ? a[0] - b[0] : b[1] - a[1]);
        
        int result = intervals.length;
        
        int rightSoFar = intervals[0][1];
        for (int i = 1; i < intervals.length; i++) {
            if (intervals[i][1] <= rightSoFar) {
                result -= 1;
            } else {
                rightSoFar = intervals[i][1];
            }
        }
        
        return result;
    }
}