<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:
    int minAreaRect(vector<vector<int>>& points) {
        unordered_map<int, unordered_set<int>> x_to_y_table;

        for (int i = 0; i < points.size(); ++i) {
            x_to_y_table[points[i][0]].insert(points[i][1]);
        }

        int ans = INT_MAX;
        bool ans_exist = false;
        for (int i = 0; i < points.size(); ++i) {
            vector<int> p1 = points[i];
            for (int j = i+1; j < points.size(); ++j) {
                vector<int> p2 = points[j];
                if (p1[0] == p2[0] || p1[1] == p2[1]) {
                    continue;
                }

                if (x_to_y_table[p1[0]].count(p2[1]) && x_to_y_table[p2[0]].count(p1[1])) {
                    ans = std::min(ans, std::abs(p1[0]-p2[0])*std::abs(p1[1]-p2[1]));
                    ans_exist = true;
                }

            }
        }

        return ans_exist ? ans : 0;
    }
};
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