Compilare: main.cpp: In function 'bool cuplaj(int)': main.cpp:18:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0;j<l[i].size();j++) ~^~~~~~~~~~~~ main.cpp:29:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0;j<l[i].size();j++) ~^~~~~~~~~~~~ main.cpp:40:1: warning: control reaches end of non-void function [-Wreturn-type] } ^