Compilare: user.cpp: In function ‘void ins(const int&, const int&)’: user.cpp:11:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<H[l].size();++i){ ^ user.cpp: At global scope: user.cpp:19:6: warning: ISO C++ forbids declaration of ‘main’ with no type [-Wreturn-type] main(){ ^ user.cpp: In function ‘int main()’: user.cpp:32:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<H[i].size();++j){ ^