Compilare: main.cpp: In function 'std::vector<int> solve(int)': main.cpp:46:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < an.size(); ++j) { ~~^~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:63:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < ans.size(); ++i) { ~~^~~~~~~~~~~~ main.cpp: In function 'std::vector<int> solve(int)': main.cpp:57:1: warning: control reaches end of non-void function [-Wreturn-type] } ^