foo.cc: In function 'int dfs(int, int)':
foo.cc:11:32: warning: unused variable 'i' [-Wunused-variable]
  int ykb,size=xyq[root].size(),i,v,Max=0;
                                ^
foo.cc: In function 'int main()':
foo.cc:70:6: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   k=l+r>>1;
      ^
foo.cc:54:8: warning: unused variable 'i' [-Wunused-variable]
  int n,i,j,a,b,c,l,r=0,ans=-1;
        ^
foo.cc:54:10: warning: unused variable 'j' [-Wunused-variable]
  int n,i,j,a,b,c,l,r=0,ans=-1;
          ^
foo.cc:61:35: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d %d",&a,&b,&c);
                                   ^

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

{"receive":"2020-04-02T07:48:10.594Z","handle":"2020-04-02T07:48:10.594Z","cache_start":"2020-04-02T07:48:10.600Z","read_cases":"2020-04-02T07:48:14.634Z","judge":"2020-04-02T07:48:14.635Z","done":"2020-04-02T07:48:19.577Z"}