Compilare: main.cpp: In function 'void dfs(int, std::vector<int>*, char*)': main.cpp:7:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < adj[node].size(); i++) { ~~^~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:20:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("dfs.in", "r", stdin); ^ main.cpp:21:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("dfs.out", "w", stdout); ^ main.cpp:23:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%lld", &n, &m); ^ main.cpp:27:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^