shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:8:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=1;i<s.size();i++){
              ~^~~~~~~~~
shoes.cpp:9:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while(i<s.size() && st.size()>0 && st.top()<0 && s[i]>0){
         ~^~~~~~~~~
shoes.cpp:14:7: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(i==s.size()) break;
      ~^~~~~~~~~~