day-187.cpp

/*
  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.
Example 2:

Input: intervals = [[1,4],[2,3]]
Output: 1
Example 3:

Input: intervals = [[0,10],[5,12]]
Output: 2
Example 4:

Input: intervals = [[3,10],[4,10],[5,11]]
Output: 2
Example 5:

Input: intervals = [[1,2],[1,4],[3,4]]
Output: 1


Constraints:

1 <= intervals.length <= 1000
intervals[i].length == 2
0 <= intervals[i][0] < intervals[i][1] <= 10^5
All the intervals are unique.
*/

// Simple slow solution
class Solution {
   public:
    int removeCoveredIntervals(vector<vector<int>>& intervals) {
        int answer = intervals.size();

        for (int idx = 0; idx < intervals.size(); idx++) {
            for (int jdx = 0; jdx < intervals.size(); jdx++) {
                if (idx == jdx) continue;
                vector<int> first = intervals[idx];
                vector<int> current = intervals[jdx];
                if (current[0] <= first[0] && current[1] >= first[1]) {
                    answer -= 1;
                    break;
                }
            }
        }

        return answer;
    }
};