Compilare: user.cpp: In function ‘bool bfs()’: user.cpp:26:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < m[x].size(); ++i) { ^ user.cpp: In function ‘void bfs2(int)’: user.cpp:47:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < m[x].size(); ++i) { ^ user.cpp: In function ‘void update_flow()’: user.cpp:57:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<m[N].size();++i) { ^ user.cpp: In function ‘int main()’: user.cpp:85:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("critice.in","r",stdin); ^ user.cpp:86:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("critice.out","w",stdout); ^ user.cpp:87:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&N,&M); ^ user.cpp:89:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&x,&y,&z); ^