/in/foo.cc: In constructor 'MaxFlowCost::MaxFlowCost()':
/in/foo.cc:42:33: error: 'memset' was not declared in this scope
   memset(m_map, 0, sizeof(m_map));
                                 ^
/in/foo.cc: In member function 'bool MaxFlowCost::spfa(int, int, int&)':
/in/foo.cc:76:35: error: 'memset' was not declared in this scope
   memset(mark, false, sizeof(mark));
                                   ^
/in/foo.cc:93:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (int j = 0; j < v_flows[from].size(); j++)
                    ~~^~~~~~~~~~~~~~~~~~~~~~
/in/foo.cc: In member function 'int MaxFlowCost::Calc(int, int)':
/in/foo.cc:129:7: warning: unused variable 'flow' [-Wunused-variable]
   int flow = 0;
       ^~~~