Compilare: user.cpp: In function ‘void bfs(int, int)’: user.cpp:20:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[k].size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:82:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("senat.in","r",stdin); ^ user.cpp:83:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("senat.out","w",stdout); ^ user.cpp:89:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d ",&n,&m); ^ user.cpp:96:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ /tmp/ccyQ9Iks.o: In function `main': user.cpp:(.text.startup+0xa0): warning: the `gets' function is dangerous and should not be used.