foo.cc: In function 'int dijkstra(int)':
foo.cc:20:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i=0;i<g[f.x].size();i++)
                     ~^~~~~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:30:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d:%d\n%d %d",&hour,&mine,&n,&m);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:33:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d%d",&u,&v,&w);
         ~~~~~^~~~~~~~~~~~~~~~~~~
foo.cc:38:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&t,&ch);
     ~~~~~^~~~~~~~~~~~~~~

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