Compilare: main.cpp: In function 'std::pair<long long int, long long int> dfs(int, int)': main.cpp:43:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v.size(); ++i) ~~^~~~~~~~~~ main.cpp: In function 'char read_ch()': main.cpp:62:33: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(_in_buff, 1, 4096, _fin); ^ main.cpp: In function 'int main()': main.cpp:84:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("arb2.out", "w", stdout); ^