2192. All Ancestors of a Node in a Directed Acyclic Graph

class Solution {
public:
    vector<vector<int>> getAncestors(int n, vector<vector<int>>& edges) {
        vector<int> adj[n];   
        vector<int> indegree(n);
        for(auto i:edges){
            adj[i[0]].push_back(i[1]);
            indegree[i[1]]++;
        }
        queue<int> q;
        for(int i=0;i<n;++i){
            if(indegree[i]==0)
                q.push(i);
        }
        set<int> st[n];
        while(!q.empty()){
            int cur=q.front(); 
            q.pop();
            for(auto i:adj[cur]){
                st[i].insert(cur); 
                for(auto it:st[cur])
                    st[i].insert(it);
          
                indegree[i]--;
                if(indegree[i]==0)
                q.push(i);
            }
        }
        
        vector<vector<int>> ans(n);
        for(int i=0;i<n;++i)
            ans[i]=vector<int>(st[i].begin(),st[i].end());
        
        return ans; 
    }
};