Compilare: main.cpp: In function 'void solve2(int)': main.cpp:41:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i <= a; ++i) { ~~^~~~ main.cpp: In function 'void print()': main.cpp:59:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i <= a; ++i) ~~^~~~ main.cpp: In function 'int main()': main.cpp:67:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i <= a; ++i) { ~~^~~~