Compilare: user.cpp: In function ‘int main()’: user.cpp:38:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < Dp.size (); ++ i) { ~~^~~~~~~~~~~~ user.cpp:46:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < Dp.size (); ++ i) { ~~^~~~~~~~~~~~ user.cpp:54:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < Dp.size (); ++ i) { ~~^~~~~~~~~~~~ user.cpp:35:13: warning: unused variable ‘prev’ [-Wunused-variable] int prev = 1; ^~~~