Compilare: user.cpp: In function ‘int bf()’: user.cpp:22:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<L[x].size();++i) ^ user.cpp:16:9: warning: unused variable ‘i’ [-Wunused-variable] int i; ^ user.cpp: In function ‘int main()’: user.cpp:51:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<L[n].size(); i++) { ^ user.cpp:38:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("maxflow.in","r",stdin); ^ user.cpp:39:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("maxflow.out","w",stdout); ^ user.cpp:40:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:43:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&x,&y,&z); ^