/in/foo.cc: In function 'void add_edge(int, int, int)':
/in/foo.cc:11:42: warning: narrowing conversion of 'G[v].std::vector<edge>::size()' from 'std::vector<edge>::size_type {aka long unsigned int}' to 'int' inside { } [-Wnarrowing]
     G[u].push_back((edge){v,cap,G[v].size()});
                                 ~~~~~~~~~^~
/in/foo.cc:12:42: warning: narrowing conversion of '(G[u].std::vector<edge>::size() - 1)' from 'std::vector<edge>::size_type {aka long unsigned int}' to 'int' inside { } [-Wnarrowing]
     G[v].push_back((edge){u,0,G[u].size()-1});
                               ~~~~~~~~~~~^~