foo.cc: In function 'bool cmp_v(std::vector<int>, std::vector<int>)':
foo.cc:22:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(i=0;i<v1.size();i++) {
          ~^~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:50:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(k=0;k<last_temp_v.size();k++) {
             ~^~~~~~~~~~~~~~~~~~~
foo.cc:79:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(i=0;i<trace[full].size();i++) {
           ~^~~~~~~~~~~~~~~~~~~
foo.cc:32:8: warning: unused variable 'm' [-Wunused-variable]
  int n,m;
        ^
foo.cc:33:6: warning: unused variable 'p' [-Wunused-variable]
  int p,q;
      ^
foo.cc:33:8: warning: unused variable 'q' [-Wunused-variable]
  int p,q;
        ^