Compilare: user.cpp: In function ‘void bfs(int)’: user.cpp:21:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[k].size();i++) ^ user.cpp: In function ‘void bfs2()’: user.cpp:45:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[y].size();++i) ^ user.cpp:60:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int f=0;f<v[x].size();f++) ^ user.cpp: In function ‘int main()’: user.cpp:95:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<sol.size();i++) ^ user.cpp:77:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("graf.in", "r", stdin); ^ user.cpp:78:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("graf.out", "w", stdout); ^ user.cpp:80:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i %i %i %i", &n, &m, &x, &y); ^ user.cpp:84:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i %i", &a, &b); ^