Leetcode75/CourseSchedular.cpp at main · aishwarya1735/Leetcode75 · GitHub

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class Solution {
public:
    vector<int> findOrder(int V, vector<vector<int>>& a) {


        vector<int>adj[V+1];
        for(int i=0;i<a.size();i++){


            adj[a[i][1]].push_back(a[i][0]);
        }


        	    vector<int>indegree(V,0);

	    for(int i=0;i<V;i++){


	        for(auto it : adj[i]){

	            indegree[it]++;
	        }
	    }

	    queue<int>q;
	    for(int i=0;i<V;i++){

	        if(indegree[i]==0){

	            q.push(i);
	        }
	    }

	    vector<int>v;
	    while(!q.empty()){


	        int x=q.front();
	        v.push_back(x);
	        q.pop();

	        for(auto it : adj[x]){

	            indegree[it]--;
	            if(indegree[it]==0)q.push(it);
	        }


	    }
	    if(v.size()!=V){

            return {};
        }
	    return v;
    }
};