/in/foo.cc: In function 'newpair ZKW_DFS(int, int, int)':
/in/foo.cc:128:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<edgenode>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  128 |     for (int& z = head[x]; z < edge[x].size(); z++) {
      |                            ~~^~~~~~~~~~~~~~~~
/in/foo.cc: In function 'void costflow()':
/in/foo.cc:154:20: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
  154 |         while (ans = ZKW_DFS(0, st, inf)) {
      |                ~~~~^~~~~~~~~~~~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:179:19: warning: unused variable 'flow' [-Wunused-variable]
  179 |         int x, y, flow, weight;
      |                   ^~~~