Compilare: user.cpp: In function ‘void Make_Prime_Powers()’: user.cpp:31:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < V.size(); i++) ^ user.cpp: In function ‘void Verif(int)’: user.cpp:47:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (P[sol[i]].size() <= put[i]) return; ^ user.cpp: In function ‘void Back1(int, int)’: user.cpp:84:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = sol[k - 1] + 1; i < V.size(); i++) ^ user.cpp:88:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (sum < P[sol[1]].size()) Back1(k + 1, m); ^ user.cpp: In function ‘int main()’: user.cpp:103:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < S.size(); i++) fout << S[i] << '\n'; ^