<p>You are given an array of points in the <strong>X-Y</strong> plane <code>points</code> where <code>points[i] = [x<sub>i</sub>, y<sub>i</sub>]</code>.</p>

<p>Return <em>the minimum area of a rectangle formed from these points, with sides parallel to the X and Y axes</em>. If there is not any such rectangle, return <code>0</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/08/03/rec1.JPG" style="width: 500px; height: 447px;" />
<pre>
<strong>Input:</strong> points = [[1,1],[1,3],[3,1],[3,3],[2,2]]
<strong>Output:</strong> 4
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/08/03/rec2.JPG" style="width: 500px; height: 477px;" />
<pre>
<strong>Input:</strong> points = [[1,1],[1,3],[3,1],[3,3],[4,1],[4,3]]
<strong>Output:</strong> 2
</pre>

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

<ul>
	<li><code>1 &lt;= points.length &lt;= 500</code></li>
	<li><code>points[i].length == 2</code></li>
	<li><code>0 &lt;= x<sub>i</sub>, y<sub>i</sub> &lt;= 4 * 10<sup>4</sup></code></li>
	<li>All the given points are <strong>unique</strong>.</li>
</ul>

class Solution {
public:
/*
    xpoints, ypoints, allPoints? 
    map<int, set<int>> xAtY;
    map<int, set<int>> yAtX;
    map<int, map<int, int>> exists? 
*/
    

    int getArea(int x, int y, vector<vector<int>> &xAtY, vector<vector<int>> &yAtX, map<int, map<int, int>> &exists){
        int ans = INT_MAX;
        for(int i=0;i<xAtY[y].size();i++){
            for(int j=0;j<yAtX[x].size();j++){
                int x_ = xAtY[y][i];
                int y_ = yAtX[x][j];
                if(exists[x_][y_] > 0){
                    int area = abs(x-x_) * abs(y-y_);
                    // cout<<x<<" "<<x_<<","<<y<<" "<<y_<<","<<area<<endl;
                    if(area!=0) ans = min(ans, area);
                }
            }
        }
        return ans;
    }
    int minAreaRect(vector<vector<int>>& points) {
        vector<vector<int>> xAtY(40001);
        vector<vector<int>> yAtX(40001);
        map<int , map<int, int>> exists;
        int ans = INT_MAX;
        for(auto point : points){
            int x = point[0];
            int y = point[1];
            exists[x][y] = 1;
            xAtY[y].push_back(x);
            yAtX[x].push_back(y);
        }

        for(auto point : points){
            int x = point[0];
            int y = point[1];
            ans = min(ans, getArea(x, y, xAtY, yAtX, exists));
        }

        return ans == INT_MAX ? 0 : ans;
    }
};
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