foo.cc: In function 'int main()':
foo.cc:34:37: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
     for(int i=1;i<=n;i++)gets(s[i]+1);
                                     ^
In file included from /usr/include/c++/7/cstdio:42:0,
                 from /usr/include/c++/7/ext/string_conversions.h:43,
                 from /usr/include/c++/7/bits/basic_string.h:6361,
                 from /usr/include/c++/7/string:52,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from foo.cc:1:
/usr/include/stdio.h:638:14: note: declared here
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^~~~
foo.cc:43:24: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
     printf("%d\n",Bfs()+1>>1);
                   ~~~~~^~
foo.cc:30:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     freopen("maze.in","r",stdin);
     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
foo.cc:31:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     freopen("maze.out","w",stdout);
     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
foo.cc:32:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&m,&n);c=getchar();
     ~~~~~^~~~~~~~~~~~~~
foo.cc:34:30: warning: ignoring return value of 'char* gets(char*)', declared with attribute warn_unused_result [-Wunused-result]
     for(int i=1;i<=n;i++)gets(s[i]+1);
                          ~~~~^~~~~~~~
/tmp/cce8jXmR.o: In function `main':
foo.cc:(.text.startup+0x9e): warning: the `gets' function is dangerous and should not be used.

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

{"receive":"2020-05-23T09:11:42.265Z","handle":"2020-05-23T09:11:42.265Z","cache_start":"2020-05-23T09:11:42.271Z","read_cases":"2020-05-23T09:11:42.394Z","judge":"2020-05-23T09:11:42.395Z","done":"2020-05-23T09:11:42.799Z"}