answer.code:6:1: error: ‘vector’ does not name a type
    6 | vector <int> v [750000];
      | ^~~~~~
answer.code: In function ‘void dfs(int, int, int)’:
answer.code:14:24: error: ‘v’ was not declared in this scope
   14 |     for(int i = 0; i < v[x].size(); i++){
      |                        ^
answer.code: In function ‘int main()’:
answer.code:50:9: error: ‘v’ was not declared in this scope
   50 |         v[a].push_back(b);
      |         ^
answer.code:53:8: error: too few arguments to function ‘void dfs(int, int, int)’
   53 |     dfs(1, 0);
      |     ~~~^~~~~~
answer.code:11:6: note: declared here
   11 | void dfs(int x, int p, int d){
      |      ^~~