Compilare: user.cpp: In function ‘void bfsx()’: user.cpp:19:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<g[crt].size(); i++) ^ user.cpp: In function ‘void bfsy()’: user.cpp:38:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<g[crt].size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:50:33: 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:51:35: 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:52:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d",&n,&m,&x,&y); ^ user.cpp:55:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&a,&b); ^