Compilare: main.cpp: In function 'int main()': main.cpp:27:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0; j<v[old].size(); ++j) ~^~~~~~~~~~~~~~ main.cpp:33:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0; j<v[old].size()-1; ++j) ~^~~~~~~~~~~~~~~~ main.cpp:38:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k=0; k<v[old][j].size(); ++k) s.push_back(v[old][j][k]); ~^~~~~~~~~~~~~~~~~ main.cpp:39:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k=0; k<v[old][j+1].size(); ++k) s.push_back(v[old][j+1][k]); ~^~~~~~~~~~~~~~~~~~~ main.cpp:48:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0; j<v[old].size(); ++j) ~^~~~~~~~~~~~~~