foo.cc: In function 'int dijkstra(int)':
foo.cc:34:16: 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:53:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%c",&t,&ch);
     ~~~~~^~~~~~~~~~~~~~~

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