<p>There is a strange printer with the following two special requirements:</p>

<ul>
	<li>On each turn, the printer will print a solid rectangular pattern of a single color on the grid. This will cover up the existing colors in the rectangle.</li>
	<li>Once the printer has used a color for the above operation, <strong>the same color cannot be used again</strong>.</li>
</ul>

<p>You are given a <code>m x n</code> matrix <code>targetGrid</code>, where <code>targetGrid[row][col]</code> is the color in the position <code>(row, col)</code> of the grid.</p>

<p>Return <code>true</code><em> if it is possible to print the matrix </em><code>targetGrid</code><em>,</em><em> otherwise, return </em><code>false</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/12/23/print1.jpg" style="width: 600px; height: 175px;" />
<pre>
<strong>Input:</strong> targetGrid = [[1,1,1,1],[1,2,2,1],[1,2,2,1],[1,1,1,1]]
<strong>Output:</strong> true
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/12/23/print2.jpg" style="width: 600px; height: 367px;" />
<pre>
<strong>Input:</strong> targetGrid = [[1,1,1,1],[1,1,3,3],[1,1,3,4],[5,5,1,4]]
<strong>Output:</strong> true
</pre>

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

<pre>
<strong>Input:</strong> targetGrid = [[1,2,1],[2,1,2],[1,2,1]]
<strong>Output:</strong> false
<strong>Explanation:</strong> It is impossible to form targetGrid because it is not allowed to print the same color in different turns.
</pre>

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

<ul>
	<li><code>m == targetGrid.length</code></li>
	<li><code>n == targetGrid[i].length</code></li>
	<li><code>1 &lt;= m, n &lt;= 60</code></li>
	<li><code>1 &lt;= targetGrid[row][col] &lt;= 60</code></li>
</ul>

class Solution {
    bool isRect(vector<vector<int>>& grid, int c, int x1, int y1, int x2, int y2) {
        for (int i = x1; i <= x2; ++i) {
            for (int j = y1; j <= y2; ++j) {
                if (grid[i][j] != c && grid[i][j] != 0) return false;
            }
        }

        return true;
    }

    void remove(vector<vector<int>>& grid, int x1, int y1, int x2, int y2) {
        for (int i = x1; i <= x2; ++i) {
            for (int j = y1; j <= y2; ++j) {
                grid[i][j] = 0;
            }
        }
    }

public:
    bool isPrintable(vector<vector<int>>& grid) {
        int m = grid.size();
        int n = grid[0].size();
        unordered_map<int, vector<int>> colors; // color => [top, left, bottom, right]

        for (int i = 0; i < m; ++i) {
            for (int j = 0; j < n; ++j) {
                int c = grid[i][j];                

                if (!colors.contains(c)) {
                    colors[c] = { i, j, i, j };
                } else {
                    colors[c][0] = min(i, colors[c][0]); // top
                    colors[c][1] = min(j, colors[c][1]); // left
                    colors[c][2] = max(i, colors[c][2]);
                    colors[c][3] = max(j, colors[c][3]);
                }
            }
        }

        int cntColors = colors.size();

        for (int i = 0; i < cntColors; ++i) {
            int paint = 0;

            for (auto pi : colors) {
                int color = pi.first;
                auto coords = pi.second;

                if (isRect(grid, color, coords[0], coords[1], coords[2], coords[3])) {
                    paint = color;
                    break;
                }
            }

            if (paint == 0) return false;

            remove(grid, colors[paint][0], colors[paint][1], colors[paint][2], colors[paint][3]);
            colors.erase(paint);
        }

        return true;
    }
};
19023