Compilare: user.cpp: In function ‘void solve()’: user.cpp:102:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(S.size() < k) ^ user.cpp: In function ‘int main()’: user.cpp:154:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("naveplanare.in", "r", stdin); ^ user.cpp:155:44: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("naveplanare.out", "w", stdout); ^ user.cpp:157:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &k); ^ user.cpp:160:42: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &p[i].fi, &p[i].se); ^