Compilare: user.cpp: In function ‘void add_solution(int, int, int)’: user.cpp:179:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < act.size(); i++) { ^ user.cpp:248:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < act.size(); i++) ^ user.cpp:174:9: warning: unused variable ‘i’ [-Wunused-variable] int i, j, target; ^ user.cpp:174:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j, target; ^ user.cpp: In function ‘int main()’: user.cpp:306:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 1; i + 2 < way.size(); i += 2) ^ user.cpp:257:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("santa.out","w",stdout); ^ user.cpp: In member function ‘void Buffer::refill()’: user.cpp:69:43: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(&data[0], 1, dim, stdin); ^ user.cpp: In constructor ‘Buffer::Buffer(std::string, int)’: user.cpp:38:46: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(name.c_str(), "r", stdin); ^