Compilare: main.cpp: In function 'void bfs(int)': main.cpp:14:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[q.front()].size();i++) ~^~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:25:32: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("bfs.in","r",stdin); ^ main.cpp:26:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("bfs.out","w",stdout); ^