Compilare: main.cpp: In function 'bool ok(int)': main.cpp:54:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<ans.size();j++) ~^~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:79:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(ok(i) && ans.size()==n) ~~~~~~~~~~^~~ main.cpp:82:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<ans.size();i++) ~^~~~~~~~~~~