Compilare: user.cpp: In function ‘void add_to_result(std::string)’: user.cpp:13:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = result.size(); i < sol.size(); ++i) ^ user.cpp:15:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = sol.size(); i < result.size(); ++i) ^ user.cpp:17:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < result.size(); ++i) { ^ user.cpp: In function ‘std::string get_string(std::vector<int>&)’: user.cpp:28:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v.size(); ++i) ^ user.cpp: In function ‘void bkt(std::vector<int>&)’: user.cpp:37:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < s.size(); ++i) { ^ user.cpp:39:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < sol.size(); ++j) ^ user.cpp:49:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i+1 < s.size() && s[i+1] == s[i]) ^