foo.cc: In function 'void add_edge(int, int, int, int)':
foo.cc:16:40: warning: narrowing conversion of 'g[to].std::vector<edge>::size()' from 'std::vector<edge>::size_type' {aka 'long unsigned int'} to 'int' [-Wnarrowing]
   16 |     edge a = { to, cap, cost,g[to].size() };
      |                              ~~~~~~~~~~^~
foo.cc:18:44: warning: narrowing conversion of '(g[from].std::vector<edge>::size() - 1)' from 'std::vector<edge>::size_type' {aka 'long unsigned int'} to 'int' [-Wnarrowing]
   18 |     edge b = { from,0,-cost,g[from].size() - 1 };
      |                             ~~~~~~~~~~~~~~~^~~
foo.cc: In function 'int min_cost_flow(int, int, int)':
foo.cc:36:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<edge>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |                 for (i = 0; i < g[v].size(); i++)
      |                             ~~^~~~~~~~~~~~~

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