<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 isPrintable(vector<vector<int>>& v) {
        vector<vector<int>>w(61,{INT_MAX,INT_MAX,INT_MIN,INT_MIN});
        int n=v.size();
        int m=v[0].size();
        for(int i=0;i<n;i++){
            for(int j=0;j<m;j++){
                int a=v[i][j];
                w[a][0]=min(w[a][0],i);
                w[a][1]=min(w[a][1],j);
                w[a][2]=max(w[a][2],i);
                w[a][3]=max(w[a][3],j);
            }
        }
        vector<vector<int>>g(61);
        vector<int>ind(61,0);
        for(int i=1;i<=60;i++){
            int sx=w[i][0];
            int sy=w[i][1];
            int ex=w[i][2];
            int ey=w[i][3];
            for(int x=sx;x<=ex;x++){
                for(int y=sy;y<=ey;y++){
                    if(v[x][y]!=i){
                        g[v[x][y]].push_back(i);
                        ind[i]++;
                    }
                }
            }
        }
        vector<int>res;
        queue<int>q;
        for(int i=1;i<=60;i++){
            if(!ind[i]){ 
                q.push(i);
                res.push_back(i);
            }
        }
        while(!q.empty()){
            auto node=q.front(); q.pop();
            for(auto fnode:g[node]){
                ind[fnode]--;
                if(!ind[fnode]){
                    q.push(fnode);
                    res.push_back(fnode);
                }
            }
        }
        cout<<res.size()<<endl;
        if(res.size()==60) return true;
        return false;
    }
};
42419