Minimum Number of Vertices to Reach All Nodes LeetCode solution in C++

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class Solution {
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 public:
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  vector<int> findSmallestSetOfVertices(int n, vector<vector<int>> &edges) {
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    vector<int> ans;
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    vector<int> indegree(n + 2), outdegree(n + 2);
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    for (auto i : edges) {
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      indegree[i[1]]++;
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      outdegree[i[0]]++;
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    }
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    for (int i = 0; i < n; i++) {
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      if (indegree[i] == 0 && outdegree[i] != 0) {
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        ans.push_back(i);
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      }
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    }
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    return ans;
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  }
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};