foo.cc:46:2: error: 'bfs' function uses 'auto' type specifier without trailing return type
   46 |  auto bfs() {
      |  ^~~~
foo.cc:46:2: note: deduced return type only available with '-std=c++14' or '-std=gnu++14'
foo.cc: In function 'int main()':
foo.cc:88:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   88 |                 scanf("%d", &sta.m[i][j]);
      |                 ~~~~~^~~~~~~~~~~~~~~~~~~~

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