foo.cc: In function 'void print_by_2(int)':
foo.cc:12:2: error: 'itoa' was not declared in this scope
  itoa(val,buf,2);
  ^~~~
foo.cc:12:2: note: suggested alternative: 'atol'
  itoa(val,buf,2);
  ^~~~
  atol
foo.cc: In function 'int press(int, int)':
foo.cc:18:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  for(int i=1;i<=G[bnt][0];++i)
  ^~~
foo.cc:20:6: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
      return val;
      ^~~~~~
foo.cc: In function 'void bfs()':
foo.cc:43:1: error: a function-definition is not allowed here before '{' token
 {
 ^
foo.cc:68:1: error: expected '}' at end of input
 }
 ^

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