Compilare: user.cpp: In function ‘void add(std::vector<std::pair<int, int> >&, std::pair<int, int>, int)’: user.cpp:20:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(v.size() < k) v.push_back(x); ^ user.cpp: In function ‘int main()’: user.cpp:50:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("statiuni.in", "r", stdin); ^ user.cpp:51:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("statiuni.out", "w", stdout); ^ user.cpp:53:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &k); ^ user.cpp:55:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^