/in/foo.cc: In function 'int main()':
/in/foo.cc:11:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define FOR(i,x,y) for(i=x;i<=y;++i)
                              
/in/foo.cc:66:13:
         FOR(j,0,e[i].v.size()-1){
             ~~~~~~~~~~~~~~~~~~~
/in/foo.cc:66:9: note: in expansion of macro 'FOR'
         FOR(j,0,e[i].v.size()-1){
         ^~~
/in/foo.cc:11:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define FOR(i,x,y) for(i=x;i<=y;++i)
                              
/in/foo.cc:68:13:
         FOR(k,0,e[0].v.size()-1)
             ~~~~~~~~~~~~~~~~~~~
/in/foo.cc:68:9: note: in expansion of macro 'FOR'
         FOR(k,0,e[0].v.size()-1)
         ^~~