foo.cc: In function 'void Bellman_Ford(long long int)':
foo.cc:28:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         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]
     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]
         scanf("%lld %lld %lld",&x,&y,&z);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务