/in/foo.cc: In function 'void dfs(long long int, long long int, long long int)':
/in/foo.cc:47:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i=0;i<edge[x].size();i++){
                ~^~~~~~~~~~~~~~~
/in/foo.cc: In function 'bool can(long long int)':
/in/foo.cc:97:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (int j=0;j<edge[x].size();j++){ 
                 ~^~~~~~~~~~~~~~~
/in/foo.cc:113:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int j=0;j<edge[x].size();j++){
                  ~^~~~~~~~~~~~~~~
/in/foo.cc:122:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int j=0;j<edge[x].size();j++){
                  ~^~~~~~~~~~~~~~~