Compilare: main.cpp: In function 'int main()': main.cpp:16:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(d.size() == k){ ~~~~~~~~~^~~~ main.cpp:31:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(d.size() == k){ ~~~~~~~~~^~~~ main.cpp:51:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(d.size() == k){ ~~~~~~~~~^~~~ main.cpp:71:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(d.size() == k){ ~~~~~~~~~^~~~