foo.cc: In function 'int mat(int, int)':
foo.cc:18:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j=i;j<=s[fir].size()-1;j++)
               ~^~~~~~~~~~~~~~~~~
foo.cc: In function 'void dfs(int)':
foo.cc:38:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(mp[x][i]==s[x].size()||mp[x][i]==s[i].size())continue;
      ~~~~~~~~^~~~~~~~~~~~~
foo.cc:38:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(mp[x][i]==s[x].size()||mp[x][i]==s[i].size())continue;
                             ~~~~~~~~^~~~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:55:10: warning: variable 'start' set but not used [-Wunused-but-set-variable]
  clock_t start, finish;
          ^~~~~
foo.cc:55:17: warning: unused variable 'finish' [-Wunused-variable]
  clock_t start, finish;
                 ^~~~~~
foo.cc: In function 'int mat(int, int)':
foo.cc:31:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

自豪的采用jd5进行评测(github.com/masnn/jd5)

{"receive":"2020-02-26T03:38:16.036Z","handle":"2020-02-26T03:38:16.036Z","cache_start":"2020-02-26T03:38:16.036Z","read_cases":"2020-02-26T03:38:16.207Z","judge":"2020-02-26T03:38:16.208Z","done":"2020-02-26T03:38:18.130Z"}