/in/foo.cc: In function 'void build(int, int, int)':
/in/foo.cc:29:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0; i<exist[cnt].size(); i++)First[cnt][exist[cnt][i]]=0x3f3f3f3f,Last[cnt][exist[cnt][i]]=0;
               ~^~~~~~~~~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:61:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int i=0; i<exist[x].size(); i++)
                 ~^~~~~~~~~~~~~~~~
/in/foo.cc:96:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0; i<exist[L].size(); i++)
                ~^~~~~~~~~~~~~~~~
/in/foo.cc:99:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int i=0; i<exist[R].size(); i++)
                 ~^~~~~~~~~~~~~~~~
/in/foo.cc:102:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int i=0; i<exist[L].size(); i++)
                 ~^~~~~~~~~~~~~~~~