All Paths From Source to Target LeetCode solution in C++

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class Solution {
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 public:
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  // setting a few class variables, so that we do not have to pass them down all
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  // the time in the recursive dfs calls
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  int target;
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  vector<vector<int>> res;
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  vector<int> tmp;
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  void dfs(vector<vector<int>> &graph, int currNode = 0) {
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    // updating tmp
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    tmp.push_back(currNode);
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    // and either updating res with it if target is met
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    if (currNode == target) res.push_back(tmp);
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    // or callling dfs again recursively
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    else
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      for (int node : graph[currNode]) {
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        dfs(graph, node);
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      }
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    // backtracking with tmp
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    tmp.pop_back();
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  }
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  vector<vector<int>> allPathsSourceTarget(vector<vector<int>> &graph) {
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    target = graph.size() - 1;
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    dfs(graph);
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    return res;
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  }
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};