Compilare: main.cpp: In function 'int main()': main.cpp:34:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<after[pos].size();i++) ~^~~~~~~~~~~~~~~~~~ main.cpp:51:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<after[i].size();j++) ~^~~~~~~~~~~~~~~~ main.cpp:62:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<after[i].size();j++) ~^~~~~~~~~~~~~~~~