Compilare: user.cpp: In function ‘long long int fromVector(std::vector<int>&)’: user.cpp:19:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < digits.size(); i++) { ^ user.cpp: In function ‘long long int fromVector(int, std::vector<int>&)’: user.cpp:27:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < digits.size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:66:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < digits.size() - 1; ++i) { ^ user.cpp:53:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("gap.in", "r", stdin); ^ user.cpp:54:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("gap.out", "w", stdout); ^ user.cpp:56:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &T); ^ user.cpp:60:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld", &n); ^