<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 {
public:
    bool isCyclic(int n, unordered_map<int, unordered_set<int>> &adj)
    {
        vector<int> inDegree(n, 0);
        for(auto it: adj)
        {
            for(auto i: it.second) inDegree[i]++;
        }
        queue<int> q;
        int topoNodes = 0;
        for(int i=0; i<n; i++) if(inDegree[i] == 0) q.push(i);
        while(!q.empty())
        {
            int node = q.front();
            q.pop();
            topoNodes++;
            for(auto it: adj[node])
            {
                if(--inDegree[it] == 0) q.push(it);
            }
        }
        return topoNodes == n;
    }
    bool isPrintable(vector<vector<int>>& arr) {
        int n = arr.size(), m = arr[0].size();
        unordered_map<int, unordered_set<int>> adj;
        int colors = 61;
        for(int color = 0; color < colors; color++)
        {
            int minx = INT_MAX, miny = INT_MAX;
            int maxx = INT_MIN, maxy = INT_MIN;
            for(int i = 0; i<n; i++)
            {
                for(int j=0; j<m; j++)
                {
                    if(arr[i][j] == color)
                    {
                        minx = min(i, minx);
                        maxx = max(i, maxx);
                        miny = min(j, miny);
                        maxy = max(j, maxy);
                    }
                }
            }
            for(int i=minx; i<=maxx; i++)
            {
                for(int j=miny;j<=maxy;j++)
                {
                    if(arr[i][j] != color)
                    {
                        adj[color].insert(arr[i][j]);
                    }
                }
            }
        }
        return isCyclic(colors, adj);
    }
};
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