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Course_Schedule_2
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Course_Schedule_2
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bool kahnalgo(vector<vector<int>>&adj,int n,vector<int>&indegree,vector<int>&ans)
{
queue<int>q;
for(int i=0;i<n;i++)
{
if(indegree[i]==0)
q.push(i);
}
int count=0;
while(!q.empty())
{
int curr=q.front();
q.pop();
for(auto a:adj[curr])
{
indegree[a]--;
if(indegree[a]==0)
q.push(a);
}
ans.push_back(curr);
count++;
}
if(count!=n)
return false;
return true;
}
vector<int> findOrder(int numCourses, vector<vector<int>>& prerequisites) {
int n=prerequisites.size();
vector<vector<int>>adj(numCourses);
vector<int>indegree(numCourses,0);
for(int i=0;i<n;i++)
{
adj[prerequisites[i][1]].push_back(prerequisites[i][0]);
indegree[prerequisites[i][0]]++;
}
vector<int>ans;
if(kahnalgo(adj,numCourses,indegree,ans))
return ans;
return {};
}