<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:
int toposort(vector<int> g[]) {
    vector<int> indeg(61, 0);
    for(int i = 1; i <= 60; i++) {
        for(auto& b: g[i]) indeg[b]++;
    }

    queue<int> q;
    vector<int> topo;
    for(int i = 1; i <= 60; i++) {
        if(indeg[i] == 0) q.push(i);
    }

    while(!q.empty()) {
        int node = q.front(); q.pop();
        topo.push_back(node);

        for(auto& b: g[node]) {
            indeg[b]--;
            if(indeg[b] == 0) q.push(b);
        }
    }
    return topo.size();
}
    bool isPrintable(vector<vector<int>>& grid) {
        int n = grid.size(), m = grid[0].size();
        map<int, vector<int>> dim;
        vector<int> g[61];
        for(int val = 1; val <= 60; val++) {
            // l r u d
            dim[val] = {100, -1, 100, -1};
            for(int i = 0; i < n; i++) {
                for(int j = 0; j < m; j++) {
                    if(grid[i][j] == val) {
                        dim[val][0] = min(dim[val][0], j);
                        dim[val][1] = max(dim[val][1], j);
                        dim[val][2] = min(dim[val][2], i);
                        dim[val][3] = max(dim[val][3], i);
                    }
                }
            }
        }

        for(int val = 1; val <= 60; val++) {
            int l = dim[val][0], r = dim[val][1], u = dim[val][2], d = dim[val][3];
            for(int i = u; i <= d; i++) {
                for(int j = l; j <= r; j++) {
                    if(grid[i][j] != val) g[val].push_back(grid[i][j]);
                }
            }
        }

        return toposort(g) == 60;
    }
};
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