foo.cc: In function 'void dfs(ll, ll)':
foo.cc:19:2: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  if(!n) return; n--;
  ^~
foo.cc:19:17: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
  if(!n) return; n--;
                 ^
foo.cc:21:2: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  if(t) k^=(1llu<<n)-1; dfs(n,k);
  ^~
foo.cc:21:24: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
  if(t) k^=(1llu<<n)-1; dfs(n,k);
                        ^~~

自豪的采用 HydroJudge 进行评测(github.com/hydro-dev/HydroJudge)

正在同步测试数据，请稍后
{"receive":"2020-07-30T14:17:51.869Z","handle":"2020-07-30T14:17:51.869Z","cache_start":"2020-07-30T14:17:51.913Z","read_cases":"2020-07-30T14:17:52.514Z","judge":"2020-07-30T14:17:52.515Z","done":"2020-07-30T14:17:54.691Z"}