<p>You are given a 2D array of axis-aligned <code>rectangles</code>. Each <code>rectangle[i] = [x<sub>i1</sub>, y<sub>i1</sub>, x<sub>i2</sub>, y<sub>i2</sub>]</code> denotes the <code>i<sup>th</sup></code> rectangle where <code>(x<sub>i1</sub>, y<sub>i1</sub>)</code> are the coordinates of the <strong>bottom-left corner</strong>, and <code>(x<sub>i2</sub>, y<sub>i2</sub>)</code> are the coordinates of the <strong>top-right corner</strong>.</p>

<p>Calculate the <strong>total area</strong> covered by all <code>rectangles</code> in the plane. Any area covered by two or more rectangles should only be counted <strong>once</strong>.</p>

<p>Return <em>the <strong>total area</strong></em>. Since the answer may be too large, return it <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://s3-lc-upload.s3.amazonaws.com/uploads/2018/06/06/rectangle_area_ii_pic.png" style="width: 600px; height: 450px;" />
<pre>
<strong>Input:</strong> rectangles = [[0,0,2,2],[1,0,2,3],[1,0,3,1]]
<strong>Output:</strong> 6
<strong>Explanation:</strong> A total area of 6 is covered by all three rectangles, as illustrated in the picture.
From (1,1) to (2,2), the green and red rectangles overlap.
From (1,0) to (2,3), all three rectangles overlap.
</pre>

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

<pre>
<strong>Input:</strong> rectangles = [[0,0,1000000000,1000000000]]
<strong>Output:</strong> 49
<strong>Explanation:</strong> The answer is 10<sup>18</sup> modulo (10<sup>9</sup> + 7), which is 49.
</pre>

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

<ul>
	<li><code>1 &lt;= rectangles.length &lt;= 200</code></li>
	<li><code>rectanges[i].length == 4</code></li>
	<li><code>0 &lt;= x<sub>i1</sub>, y<sub>i1</sub>, x<sub>i2</sub>, y<sub>i2</sub> &lt;= 10<sup>9</sup></code></li>
	<li><code>x<sub>i1 &lt;= </sub>x<sub>i2</sub></code></li>
	<li><code>y<sub>i1 &lt;=</sub> y<sub>i2</sub></code></li>
</ul>

class Solution {
public:
    int rectangleArea(vector<vector<int>>&v) {
        set<long long int>st;
        const int mod=1e9+7;
        long long int ans=0;
        for(int i=0;i<v.size();i++) 
        {
            st.insert(v[i][0]);
            st.insert(v[i][2]);
        }

        long long int last=*(st.begin());
        auto it=st.begin();
        st.erase(st.begin());
        for(auto it:st)
        {
            long long int cur=it;
            vector<pair<long long int,long long int>>p;
            for(auto i:v)
            {
                if(i[0]<=last && cur<=i[2])
                {
                    p.push_back({(long long int)i[1],(long long int)i[3]});
                }
            }
            sort(p.begin(),p.end());
            if(p.size()==0)
            {
                last=cur;
                continue;
            }
            long long int l=p[0].first;
            long long int r=p[0].second;
            for(int j=1;j<p.size();j++)
            {
                if(p[j].first<=r)
                {
                    r=max(r,p[j].second);
                }
                else
                {
                    ans+=(r-l)*(long long int)(cur-last);
                    ans%=mod;
                    l=p[j].first;
                    r=p[j].second;
                }
            }
            ans+=(r-l)*(cur-last);
            ans%=mod;
            last=cur;
        }
        return ans;
        
    }
};
18900