<p>Given an array of <code>points</code> where <code>points[i] = [x<sub>i</sub>, y<sub>i</sub>]</code> represents a point on the <strong>X-Y</strong> plane, return <em>the maximum number of points that lie on the same straight line</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/02/25/plane1.jpg" style="width: 300px; height: 294px;" />
<pre>
<strong>Input:</strong> points = [[1,1],[2,2],[3,3]]
<strong>Output:</strong> 3
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/02/25/plane2.jpg" style="width: 300px; height: 294px;" />
<pre>
<strong>Input:</strong> points = [[1,1],[3,2],[5,3],[4,1],[2,3],[1,4]]
<strong>Output:</strong> 4
</pre>

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

<ul>
	<li><code>1 &lt;= points.length &lt;= 300</code></li>
	<li><code>points[i].length == 2</code></li>
	<li><code>-10<sup>4</sup> &lt;= x<sub>i</sub>, y<sub>i</sub> &lt;= 10<sup>4</sup></code></li>
	<li>All the <code>points</code> are <strong>unique</strong>.</li>
</ul>

class Solution {
public:
    int maxPoints(vector<vector<int>>& points) {
        if (points.size() == 1) return 1;

        int res = 2;
        //unordered_map<vector<float>, int> lines;
        unordered_map<float, unordered_map<float, vector<vector<int>*>>> lines;
        unordered_map<int, vector<vector<int>*>> verticals;

        for (int i = 0; i < points.size(); i++) {
            int x1 = points[i][0];
            int y1 = points[i][1];
            for (int j = i + 1; j < points.size(); j++) {
                int x2 = points[j][0];
                int y2 = points[j][1];

                if (x1 == x2) {
                    if (!verticals.contains(x1)) {
                        verticals.emplace(x1, 2);
                        verticals[x1][0] = &points[i];
                        verticals[x1][1] = &points[j];
                    }
                    else {
                        if (find(verticals[x1].begin(), verticals[x1].end(), &points[j]) == verticals[x1].end())
                        {
                            verticals[x1].push_back(&points[j]);
                            if (verticals[x1].size() > res)
                                res = verticals[x1].size();
                        }
                    }
                }
                else {
                    float a = (float)(y2 - y1) / (x2 - x1);
                    float b = (float)(y1 * x2 - y2 * x1) / (x2 - x1);

                    if (!lines.contains(a)) {
                        lines[a].emplace(b, 2);
                        lines[a][b][0] = &points[i];
                        lines[a][b][1] = &points[j];
                    }
                    else if (!lines[a].contains(b)) {
                        lines[a].emplace(b, 2);
                        lines[a][b][0] = &points[i];
                        lines[a][b][1] = &points[j];
                    }
                    else {
                        if (find(lines[a][b].begin(), lines[a][b].end(), &points[j]) == lines[a][b].end())
                        {
                            lines[a][b].push_back(&points[j]);
                            if (lines[a][b].size() > res)
                                res = lines[a][b].size();
                        }
                    }
                }
            }
        }

        return res;
    }
};

/*

    y1 = a * x1 + b
    y2 = a * x2 + b

    y2 - y1 = a * (x2 - x1)
    a = (y2 - y1) / (x2 - x1)

    b = y1 - a * x1
    b = y1 - x1 * (y2 - y1) / (x2 - x1)
    b = (y1 * x2 - y1 * x1 - y2 * x1 + y1 * x1) / (x2 - x1)
    b = (y1 * x2 - y2 * x1) / (x2 - x1)

*/
34706