Compilare: user.cpp: In function ‘bool bs(std::vector<std::pair<int, int> >, std::pair<int, int>)’: user.cpp:18:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (poz + step < v.size() && v[poz + step] <= x) ^ user.cpp: In function ‘bool check(int, std::pair<int, int>)’: user.cpp:26:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (k[j] < v[j].size() && v[j][k[j]] < x) ^ user.cpp: In function ‘int main()’: user.cpp:59:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (; k[0] < v[0].size(); ++k[0]) { ^