foo.cc: In function 'int bfs(int, int, int)':
foo.cc:17:22: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   17 |                 auto [x,y,step] = Q.front();
      |                      ^
foo.cc: In function 'int main()':
foo.cc:56:13: warning: unused variable 'p' [-Wunused-variable]
   56 |         int p = (rec1 < rec2 ? 1 : 2), res = 0;
      |             ^
foo.cc: In function 'int bfs(int, int, int)':
foo.cc:31:1: warning: control reaches end of non-void function [-Wreturn-type]
   31 | }
      | ^

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