Compilare: main.cpp: In function 'void solve(int)': main.cpp:36:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (ans.size () > k) ~~~~~~~~~~~~^~~ main.cpp: In function 'int main()': main.cpp:52:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("pitagora.in", "r", stdin); ^ main.cpp:53:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("pitagora.out", "w", stdout); ^