Compilare: main.cpp: In instantiation of 'SparseTable<T>::SparseTable(std::vector<_Tp>&) [with T = long long int]': main.cpp:39:28: required from here main.cpp:15:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < a.size(); ++i) { main.cpp:20:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j + (1 << (i + 1)) <= a.size(); ++j) { main.cpp: In function 'int main()': main.cpp:177:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("ksecv4.in", "r", stdin); ^ main.cpp:178:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("ksecv4.out", "w", stdout); ^