/in/foo.cc: In function 'bool mcfx::spfa(int, int)':
/in/foo.cc:29:26: warning: unused variable 'f' [-Wunused-variable]
             int v=G[i].v,f=G[i].f,c=G[i].c;
                          ^
/in/foo.cc: In function 'int mcfx::dfs(int, int, int, int)':
/in/foo.cc:41:24: warning: unused variable 'f' [-Wunused-variable]
     vis[u]=1;int ret=0,f;
                        ^