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 'int main()': main.cpp:50:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("arb2.in", "r", stdin); ^ main.cpp:51:35: 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); ^ main.cpp:54:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ main.cpp:57:38: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d", &u, &v ,&d, &c); ^