Compilare: main.cpp: In function 'bool Check()': main.cpp:62:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < ans.size(); ++i) ~~^~~~~~~~~~~~ main.cpp: In function 'void Print()': main.cpp:71:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < ans.size(); ++i) ~~^~~~~~~~~~~~ main.cpp: In function 'void Backtracking()': main.cpp:81:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (ans.size() < k) ~~~~~~~~~~~^~~