foo.cc: In function 'void Bellman_Ford(long long int)':
foo.cc:28:22: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   28 |         for(ll k=0; k<q.size(); k++){//遍历所有点
      |                     ~^~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:54:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   54 |     scanf("%lld %lld %lld",&n,&s,&m);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:57:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   57 |         scanf("%lld %lld %lld",&x,&y,&z);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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