Compilare: main.cpp: In function 'int main()': main.cpp:35:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (ans.size () == k) ~~~~~~~~~~~~^~~~ main.cpp:15:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("ksecv3.in", "r", stdin); ^ main.cpp:16:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("ksecv3.out", "w", stdout); ^