foo.cc: In function 'void dfs(int, int, int)':
foo.cc:20:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   20 |  for (int i = 0; i < infectceng[k].size(); i++) {
      |                  ~~^~~~~~~~~~~~~~~~~~~~~~
foo.cc:22:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   22 |    for (int j = 0; j < infect[infectceng[k][i]].size(); j++) {
      |                    ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:33:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   33 |  for (int i = 0; i < infectceng[k + 1].size(); i++) {
      |                  ~~^~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:42:7: warning: variable 'exist' set but not used [-Wunused-but-set-variable]
   42 |  bool exist[301] = { 0 };
      |       ^~~~~
foo.cc:41:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   41 |  scanf("%d%d", &n, &p);
      |  ~~~~~^~~~~~~~~~~~~~~~
foo.cc:46:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   46 |   scanf("%d%d", &f, &c);
      |   ~~~~~^~~~~~~~~~~~~~~~

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