Compilare: user.cpp: In function ‘void BFS(int)’: user.cpp:33:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<G[q[prim]].size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:51:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("marmelada.in", "r", stdin); ^ user.cpp:52:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("marmelada.out", "w", stdout); ^ user.cpp:55:38: 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:57:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^ user.cpp:65:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &C[i].v); ^