/in/foo.cc: In function 'int main()':
/in/foo.cc:58:3: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   if(!v[i].empty());
   ^~
/in/foo.cc:59:3: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'
   {
   ^
/in/foo.cc:63:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                 for(int k=0;k<v[i].size();k++)
                             ~^~~~~~~~~~~~