Compilare: user.cpp: In function ‘void BFS(int)’: user.cpp:19:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < G[n].size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:40:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sate.in", "r", stdin); ^ user.cpp:41:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d", &N, &M, &X, &Y); ^ user.cpp:44:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &a, &b, &c); ^ user.cpp:51:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sate.out", "w", stdout); ^