Compilare: user.cpp: In function ‘int bfs()’: user.cpp:20:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<v[x].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:54:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<v[2*n+1].size();++i) ^ user.cpp:35:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("harta.in","r",stdin); ^ user.cpp:36:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("harta.out","w",stdout); ^ user.cpp:37:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:40:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^