<p>Given an array <code>intervals</code> where <code>intervals[i] = [l<sub>i</sub>, r<sub>i</sub>]</code> represent the interval <code>[l<sub>i</sub>, r<sub>i</sub>)</code>, remove all intervals that are covered by another interval in the list.</p>

<p>The interval <code>[a, b)</code> is covered by the interval <code>[c, d)</code> if and only if <code>c &lt;= a</code> and <code>b &lt;= d</code>.</p>

<p>Return <em>the number of remaining intervals</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> intervals = [[1,4],[3,6],[2,8]]
<strong>Output:</strong> 2
<strong>Explanation:</strong> Interval [3,6] is covered by [2,8], therefore it is removed.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> intervals = [[1,4],[2,3]]
<strong>Output:</strong> 1
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= intervals.length &lt;= 1000</code></li>
	<li><code>intervals[i].length == 2</code></li>
	<li><code>0 &lt;= l<sub>i</sub> &lt; r<sub>i</sub> &lt;= 10<sup>5</sup></code></li>
	<li>All the given intervals are <strong>unique</strong>.</li>
</ul>

class Solution {
public:
    int removeCoveredIntervals(vector<vector<int>>& intervals) {

        int ctr = 0;
        vector<pair<int, pair<int,int>>> vec;
        for(auto it: intervals)
        {
            vec.push_back({it[1] - it[0], {it[0], it[1]}});
        }
        sort(vec.rbegin(), vec.rend());
        
        int n = intervals.size();
        map<int,int> rm;
        for(int i=0; i<n-1; i++)
        {
            if(rm.find(i) != rm.end())
            {
                continue;
            }
            for(int j =0; j<n; j++)
            {
                if(i==j)
                {
                    continue;
                }
                if(rm.find(j) != rm.end())
                {
                    continue;
                }
                if(vec[i].second.first >= vec[j].second.first && vec[i].second.second <= vec[j].second.second)
                {
                    ctr++;
                    rm[i] = 1;
                }
                if(vec[j].second.first >= vec[i].second.first && vec[j].second.second <= vec[i].second.second)
                {
                    ctr++;
                    rm[j] = 1;
                }
            }
        }
        return n - ctr;
        
    }
};
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