Compilare: user.cpp: In function ‘int main()’: user.cpp:13:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=S.size()-1;i++) ~^~~~~~~~~~~~ user.cpp:14:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=i+1;j<=S.size()-1;j++) ~^~~~~~~~~~~~ user.cpp:27:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=4;i<=S.size();i++) ~^~~~~~~~~~ user.cpp:31:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=S.size()-1 && ok;i++) ~^~~~~~~~~~~~ user.cpp:32:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=i+1;j<=S.size()-1 && ok;j++) ~^~~~~~~~~~~~ user.cpp:35:54: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] else {g<<Sol.size()-1<<'\n';for(int i=1;i<Sol.size();i++) g<<Sol[i]<<' ';} ~^~~~~~~~~~~