Compilare: user.cpp: In function ‘std::vector<int> bfs(int, int, std::vector<std::vector<int> >&)’: user.cpp:21:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < edges[p.first].size(); i++){ ^ user.cpp: In function ‘void solve(int, int, int, std::vector<std::vector<int> >&)’: user.cpp:75:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < ans.size(); i++){ ^ user.cpp: In function ‘int main()’: user.cpp:81:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("graf.in", "r", stdin); ^ user.cpp:82:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("graf.out", "w", stdout); ^ user.cpp:87:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d", &N, &M, &S, &D); ^ user.cpp:94:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &e1, &e2); ^