Compilare: user.cpp: In function ‘void bfs(int)’: user.cpp:19:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < V[u].size() ; i++){ ^ user.cpp: At global scope: user.cpp:51:6: warning: ISO C++ forbids declaration of ‘main’ with no type [-Wreturn-type] main(){ ^ user.cpp: In function ‘void load_graph()’: user.cpp:29:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&m); ^ user.cpp:36:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&u,&v); ^ user.cpp: In function ‘int main()’: user.cpp:52:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("amici2.in","r",stdin); ^ user.cpp:53:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("amici2.out","w",stdout); ^ user.cpp:55:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&T); ^