Compilare: user.cpp: In function ‘int main()’: user.cpp:69:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<L[1].size();i++){ ^ user.cpp:70:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<=L[2].size();j++){ ^ user.cpp:75:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k=0;k<L[j].size();k++){ ^ user.cpp:77:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int d=0;d<L[j-1].size();d++) ^ user.cpp:81:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<L[N].size();j++) ^