Find Eventual Safe States LeetCode solution in C++

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class Solution {
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 public:
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  vector<int> eventualSafeNodes(vector<vector<int>> &graph) {
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    int n = graph.size();
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    vector<bool> vis(n, false), curr_vis(n, false), safe(n, true);
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    for (int i = 0; i < n; i++)
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      if (!vis[i]) dfs(i, vis, curr_vis, safe, graph);
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    vector<int> ans;
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    for (int i = 0; i < n; i++)
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      if (safe[i]) ans.push_back(i);
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    return ans;
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  }
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  bool dfs(int i, vector<bool> &vis, vector<bool> &curr_vis, vector<bool> &safe,
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           vector<vector<int>> &graph) {
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    vis[i] = true, curr_vis[i] = true;
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    for (auto j : graph[i]) {
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      if (!vis[j]) {
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        if (dfs(j, vis, curr_vis, safe, graph) == false) return safe[i] = false;
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      } else if (curr_vis[j])
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        return safe[i] = false;
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    }
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    curr_vis[i] = false;
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    return safe[i];
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  }
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};