<p>You are given an array of <code>intervals</code>, where <code>intervals[i] = [start<sub>i</sub>, end<sub>i</sub>]</code> and each <code>start<sub>i</sub></code> is <strong>unique</strong>.</p>

<p>The <strong>right interval</strong> for an interval <code>i</code> is an interval <code>j</code> such that <code>start<sub>j</sub> &gt;= end<sub>i</sub></code> and <code>start<sub>j</sub></code> is <strong>minimized</strong>. Note that <code>i</code> may equal <code>j</code>.</p>

<p>Return <em>an array of <strong>right interval</strong> indices for each interval <code>i</code></em>. If no <strong>right interval</strong> exists for interval <code>i</code>, then put <code>-1</code> at index <code>i</code>.</p>

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

<pre>
<strong>Input:</strong> intervals = [[1,2]]
<strong>Output:</strong> [-1]
<strong>Explanation:</strong> There is only one interval in the collection, so it outputs -1.
</pre>

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

<pre>
<strong>Input:</strong> intervals = [[3,4],[2,3],[1,2]]
<strong>Output:</strong> [-1,0,1]
<strong>Explanation:</strong> There is no right interval for [3,4].
The right interval for [2,3] is [3,4] since start<sub>0</sub> = 3 is the smallest start that is &gt;= end<sub>1</sub> = 3.
The right interval for [1,2] is [2,3] since start<sub>1</sub> = 2 is the smallest start that is &gt;= end<sub>2</sub> = 2.
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> intervals = [[1,4],[2,3],[3,4]]
<strong>Output:</strong> [-1,2,-1]
<strong>Explanation:</strong> There is no right interval for [1,4] and [3,4].
The right interval for [2,3] is [3,4] since start<sub>2</sub> = 3 is the smallest start that is &gt;= end<sub>1</sub> = 3.
</pre>

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

<ul>
	<li><code>1 &lt;= intervals.length &lt;= 2 * 10<sup>4</sup></code></li>
	<li><code>intervals[i].length == 2</code></li>
	<li><code>-10<sup>6</sup> &lt;= start<sub>i</sub> &lt;= end<sub>i</sub> &lt;= 10<sup>6</sup></code></li>
	<li>The start point of each interval is <strong>unique</strong>.</li>
</ul>

class Solution {
public:

struct compare {
    bool operator()(const pair<int, pair<int, int>>& a, const pair<int, pair<int, int>>& b) {
        return a.second.second > b.second.second;
    }
};

    vector<int> findRightInterval(vector<vector<int>>& intervals) {
        vector<pair<int,pair<int,int>>> modified_intervals;

        for(int i=0;i<intervals.size();i++){
            modified_intervals.push_back({i, {intervals[i][0], intervals[i][1]}});
        }

        sort(modified_intervals.begin(),modified_intervals.end(),
             [](pair<int,pair<int,int>> a, pair<int,pair<int,int>> b){
                if(a.second.first == b.second.first)
                   return a.second.second < b.second.second;
                return a.second.first < b.second.first;
             });


        vector<int> right_intervals(intervals.size(),-1);

        priority_queue<pair<int, pair<int, int>>, vector<pair<int, pair<int, int>>>, compare>  q;

        for(int i=0;i<intervals.size()-1;i++){
            if(modified_intervals[i].second.first == modified_intervals[i].second.second){
                right_intervals[modified_intervals[i].first] = modified_intervals[i].first;
            }
            else if(modified_intervals[i].second.second <= modified_intervals[i+1].second.first)
               right_intervals[modified_intervals[i].first] = modified_intervals[i+1].first;
            else{
                q.push(modified_intervals[i]);
            }
            while(!q.empty() && q.top().second.second <= modified_intervals[i+1].second.first){
                right_intervals[q.top().first] = modified_intervals[i+1].first;
                q.pop();
            }
        }

        if(modified_intervals[intervals.size()-1].second.first == modified_intervals[intervals.size()-1].second.second){
                right_intervals[modified_intervals[intervals.size()-1].first] = modified_intervals[intervals.size()-1].first;
            }
    
    return right_intervals;
    }
};
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