Compilare: user.cpp: In function ‘void bfs(int, int)’: user.cpp:16:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<g[x].size(); ++i) ^ user.cpp:30:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<g[x].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:53:33: 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:54:35: 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:56:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&n,&m,&x1,&y1); ^ user.cpp:58:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^