foo.cc: In function 'void dijkstra(int, int)':
foo.cc:45:20: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   45 |             if(u==a&&e.to==b||u==b&&e.to==a)continue;//是个无向图
      |                ~~~~^~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:58:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   58 |     scanf("%d%d",&n,&m);
      |     ~~~~~^~~~~~~~~~~~~~
foo.cc:59:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   59 |     for(int i=1;i<=n;i++)scanf("%d%d",&x[i],&y[i]);
      |                          ~~~~~^~~~~~~~~~~~~~~~~~~~
foo.cc:61:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   61 |         scanf("%d%d",&from,&to);
      |         ~~~~~^~~~~~~~~~~~~~~~~~

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