Compilare: user.cpp: In function ‘void build_paths()’: user.cpp:50:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<=4*path[i].size();j++) { ^ user.cpp: In function ‘int main()’: user.cpp:165:16: warning: unused variable ‘op’ [-Wunused-variable] int n,x,y,i,m,op,lca; ^ user.cpp:165:19: warning: unused variable ‘lca’ [-Wunused-variable] int n,x,y,i,m,op,lca; ^