/in/foo.cc: In function 'int main()':
/in/foo.cc:20:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
     for(i=1;i<=n;i++)
     ^~~
/in/foo.cc:30:2: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
  printf("有%d个细胞",ans);    
  ^~~~~~
/in/foo.cc:16:10: warning: unused variable 'k' [-Wunused-variable]
  int i,j,k;
          ^