Compilare: main.cpp: In function 'int main()': main.cpp:50:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<t1.size();++i) sol.push_back({t2[i],t1[i]}); ~^~~~~~~~~~ main.cpp:52:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<sol.size();++i) g<<sol[i].first<<' '<<sol[i].second<<'\n'; ~^~~~~~~~~~~