foo.cc: In function 'void dijkstra(int, int)':
foo.cc:45:11: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
    if(u==a&&e.to==b||u==b&&e.to==a)continue;//?????
       ~~~~^~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:57:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&m);
  ~~~~~^~~~~~~~~~~~~~
foo.cc:58:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for(int i=1; i<=n; i++)scanf("%d%d",&x[i],&y[i]);
                         ~~~~~^~~~~~~~~~~~~~~~~~~~
foo.cc:60:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",&from,&to);
   ~~~~~^~~~~~~~~~~~~~~~~~

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