Compilare: main.cpp: In function 'void dfs(int)': main.cpp:18:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(sol.size() == n) ~~~~~~~~~~~^~~~ main.cpp:21:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(!viz[i] && sol.size() < n) ~~~~~~~~~~~^~~ main.cpp:24:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(sol.size() < n) { ~~~~~~~~~~~^~~ main.cpp: In function 'int main()': main.cpp:38:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < sol.size(); i += 2) ~~^~~~~~~~~~~~