Compilare: user.cpp: In function ‘std::pair<int, bool> calc(std::vector<int>, std::vector<int>)’: user.cpp:52:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (S.size () < K) ^ user.cpp: In function ‘int main()’: user.cpp:79:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("entanglement.in", "r", stdin); ^ user.cpp:80:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("entanglement.out", "w", stdout); ^ user.cpp:82:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d %d %d", &Type, &N, &M, &K); ^ user.cpp:85:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d", &a[i][j]); ^