Compilare: user.cpp: In function ‘int main()’: user.cpp:29:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i != x.size() - 1){ ~~^~~~~~~~~~~~~~~ user.cpp:36:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < x.size() && ok; ++i){ ~~^~~~~~~~~~ user.cpp:44:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if((r[i][j] - past[j]) * 2 == x.size() - i){ ~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~ user.cpp:45:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k = i; k < x.size(); ++k){ ~~^~~~~~~~~~ user.cpp:70:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < ans.size(); ++i){ ~~^~~~~~~~~~~~