foo.cc: In function 'void Init()':
foo.cc:17:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &n, &m);
     ~~~~~^~~~~~~~~~~~~~~~
foo.cc:20:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d%d", &x[i], &y[i], &w[i]);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:23:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &f);
     ~~~~~^~~~~~~~~~

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