1288. Remove Covered Intervals

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.

class Solution {
public:
    int removeCoveredIntervals(vector<vector<int>>& intervals) {
        sort(intervals.begin(), intervals.end(), [](vector<int>& v1, vector<int>& v2){
            if(v1[0] == v2[0]) return v1[1] > v2[1];
            return v1[0] < v2[0];
        });
        int ma = intervals[0][1], res = 0;
        
        for(int i = 1; i < intervals.size(); i++) {
            if(ma >= intervals[i][1]) res++;
            else ma = intervals[i][1];
        }
        
        return intervals.size() - res;
    }
};