<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:
    void checkIfPossibleToRemove(vector<vector<int>>& targetGrid , unordered_map<int,vector<int>>&um , unordered_map<int,vector<int>>&dpg , vector<int>&degree  ,  int color){
        vector<int>cord = um[color];
        for(int i=cord[0];i<=cord[1];i++){
            for(int j=cord[2];j<=cord[3];j++){
                dpg[color].push_back(targetGrid[i][j]);
                if(color != targetGrid[i][j]){
                    degree[targetGrid[i][j]]++;
                }
            }
        }
    }

    bool checkIfCycle(unordered_map<int,vector<int>>&dpg , vector<int>&degree , unordered_map<int,int>&color ){
        queue<int>q;
        unordered_map<int,int>vis;

        for(auto it=color.begin();it!=color.end();it++){
            if(degree[it->first]==0){
                
                q.push(it->first);
            }
            cout<<degree[it->first]<<" ";
        }

        vector<int>topo;
        while(q.empty()==false){
            int u=q.front();
            q.pop();
            vis[u]++;
            cout<<u<<" ";
            topo.push_back(u);
            for(auto it:dpg[u]){
                if(--degree[it]==0){
                    q.push(it);
                }
            }
        }

        if(topo.size()!=dpg.size()){
            return false;
        }

        return true;
    }   

    bool isPrintable(vector<vector<int>>& targetGrid) {
        
        unordered_map<int,vector<int>>um,dpg;
        int n=targetGrid.size();
        int m=targetGrid[0].size();
        
        unordered_map<int,int>color;
        priority_queue<pair<int,int>,vector<pair<int,int>>,greater<pair<int,int>>>pq;
        for(int i=0;i<n;i++){
            for(int j=0;j<m;j++){
                color[targetGrid[i][j]]++;

                auto it=um.find(targetGrid[i][j]);
                if(it!=um.end()){
                    it->second[0]=min(it->second[0],i);
                    it->second[1]=max(it->second[1],i);

                    it->second[2]=min(it->second[2],j);
                    it->second[3]=max(it->second[3],j);
                }else{
                    um[targetGrid[i][j]]={i,i,j,j};
                }
               

            }
        }

        vector<int>degree(61,0);
        for(auto it=color.begin();it!=color.end();it++){
            checkIfPossibleToRemove(targetGrid, um, dpg,  degree, it->first);
        }
        return checkIfCycle(dpg ,degree , color);
    }
};
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