Compilare: user.cpp: In function ‘void remove_edge(int, int)’: user.cpp:19:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<v[a].size(); i++) ^ user.cpp:21:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<v[b].size(); i++) ^ user.cpp: In function ‘bool query_found(int, int)’: user.cpp:35:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<v[Alpha].size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:51:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("disconnect.in","r",stdin); ^ user.cpp:53:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:55:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^ user.cpp:62:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&op,&x,&y); ^