<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>

/*

https://leetcode.com/problems/remove-covered-intervals/discuss/451277/JavaC++Python-Sort-Solution

https://leetcode.com/problems/remove-covered-intervals/discuss/451284/JavaPython-3-Simple-codes-w-explanation-and-analysis.

https://leetcode.com/problems/remove-covered-intervals/discuss/451250/Java-Simple-Sort

*/

#include <algorithm>

using namespace std;

struct cmp {
    bool operator()(const vector<int>& v1, const vector<int>& v2) {
        
        if ( v1[0] != v2[0] ) {
            return v1[0] < v2[0];
        }
        return v1[1] > v2[1];
    }
};

class Solution {
public:
    int removeCoveredIntervals(vector<vector<int>>& intervals) {
        
        int n = intervals.size(), i = 0;
        
        std::sort(intervals.begin(), intervals.end(), cmp());
        
        for (int j = 1; j < n; ++j) {
            
            if ( intervals[j][0] >= intervals[i][0] && 
                 intervals[j][1] <= intervals[i][1] ) {
                continue;
            } else {
                intervals[++i] = intervals[j];
            }
        }
        
        return i + 1;
    }
};
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