foo.cc: In function 'int main()':
foo.cc:65:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int j=0;j<s.size();j++)
                     ~^~~~~~~~~

正在同步测试数据，请稍后
自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。