Why is my solution for "Cowntagion" slow?

Problems and Contests
#1

title. Here is my code, which returns TLE for almost every case:

 #include <bits/stdc++.h>
using namespace std;

int dfs(int curr, vector<vector<int>> adj) {
  int res = ceil(log((int)adj[curr].size()+1));
  for (int neighbor: adj[curr]) {
    res += 1 + dfs(neighbor, adj);
  }
  return res;
}

int main() {
  int n;
  cin >> n;
  vector<vector<int>> adj(n);
  for (int i = 0 ; i < n-1 ; i++) {
    int a, b;
    cin >> a >> b;
    adj[a-1].push_back(b-1);
  }
  int res = dfs(0, adj);
  cout << res;
  return 0;
}
#2

If it TLEs even on the first, sample test case, then you might be running into an infinite loop.

#3

no, it works on the sample case but fails everything else. it is quite similar to the dfs solution on usaco guide.

#4

You still might be running into an infinite loop. Try downloading the test data and see what happens.

#5

You need to check if (!used[next node]) then dfs(next node)

#6

But my program creates a directed tree, so the child node doesn’t point back to the parent.

#7

Have you tried downloading the test cases?
Also, I took a closer look at your code, and I think you’re assuming that all edges point away from the root; that isn’t necessarily the case.