Compilare: main.cpp: In function 'long long int solve(std::vector<int>&, int)': main.cpp:78:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < arr.size(); ++i) ~~^~~~~~~~~~~~ main.cpp:87:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < arr.size(); ++i) { ~~^~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:222:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("yamstp.out", "w", stdout); ^ main.cpp: In member function 'char InParser::read_ch()': main.cpp:127:29: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, 4096, fin); ^