Compilare: user.cpp: In function ‘void compute_pi(const string&, std::vector<int>&)’: user.cpp:17:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < str.size(); ++ i) { ^ user.cpp: In function ‘int get_first(int, int)’: user.cpp:31:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = start; i < big.size(); ++ i) { ^ user.cpp:39:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (pi[i] == smalls[index].size()) ^ user.cpp: In function ‘int main()’: user.cpp:62:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < small.size(); ++ i) ^ user.cpp:89:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (start == big.size()) { ^