foo.cc: In function 'int main()':
foo.cc:90:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d", &cost);
         ~~~~~^~~~~~~~~~~~~
foo.cc:98:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d%d", &u, &v, &cost);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

正在同步测试数据，请稍后