/in/foo.cc: In function 'void p1005()':
/in/foo.cc:124:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=1,k=0;i<str.size();){
                     ~^~~~~~~~~~~
/in/foo.cc:139:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int k=0;k<str.size();){
                 ~^~~~~~~~~~~
/in/foo.cc:145:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         while(!st.empty()&&k<str.size()){
                            ~^~~~~~~~~~~