Compilare: user.cpp: In function ‘void BFS(int, int)’: user.cpp:33:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<v[x].size(); ++i) ^ user.cpp: In function ‘int BF()’: user.cpp:63:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<G[x].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:108:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<v[o].size();++i) L[++k]=v[o][i]; ^ user.cpp:86:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("atac2.in","r",stdin); ^ user.cpp:87:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("atac2.out","w",stdout); ^ user.cpp:88:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&n,&m,&u,&o); ^ user.cpp:90:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&L[i]); ^ user.cpp:94:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^