Create 2392. Build a Matrix With Conditions

2392. Build a Matrix With Conditions

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+class Solution {
+public:
+
+    bool toposort(vector<vector<int>> &adj, vector<int> &tsort, vector<int> &ind)
+    {
+        int V = ind.size();
+        queue<int> q;
+
+        for(int i=0 ; i<V ; i++) if(ind[i] == 0) q.push(i);
+
+        while(!q.empty())
+        {
+            int u = q.front();
+            q.pop();
+            tsort.push_back(u);
+
+            for(auto &v: adj[u])
+            {
+                ind[v] -= 1;
+                if(ind[v] == 0) q.push(v);
+            }
+        }
+
+        if(tsort.size() != V) return false;
+        return true;
+    }
+    vector<vector<int>> buildMatrix(int k, vector<vector<int>>& rowConditions, vector<vector<int>>& colConditions) {
+
+        vector<vector<int>> adj_row(k, vector<int> ());
+        vector<vector<int>> adj_col(k, vector<int> ());
+
+        vector<int> ind_row(k, 0);
+        vector<int> ind_col(k, 0);
+
+        for(auto &edge: rowConditions) 
+        {
+            adj_row[edge[0]-1].push_back(edge[1]-1);
+            ind_row[edge[1]-1] += 1;
+        }
+
+        for(auto &edge: colConditions) 
+        {
+            adj_col[edge[0]-1].push_back(edge[1]-1);
+            ind_col[edge[1]-1] += 1;
+        }
+
+        vector<int> tsort_row;
+        vector<int> tsort_col;
+
+        bool notCycle_row = toposort(adj_row, tsort_row, ind_row);
+        bool notCycle_col = toposort(adj_col, tsort_col, ind_col);
+
+        if(!notCycle_row || !notCycle_col) return {};
+        vector<vector<int>> ans(k, vector<int> (k, 0));
+
+        for(int row = 0 ; row < k ; row++)
+        {
+            int col = find(tsort_col.begin(), tsort_col.end(), tsort_row[row]) - tsort_col.begin();
+            ans[row][col] = tsort_row[row]+1;
+        }
+
+        return ans;
+    }
+};