Compilare: main.cpp: In function 'void read(int&, int&, std::vector<std::vector<int> >&)': main.cpp:9:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ main.cpp:16:48: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &left_node, &right_node); ^ main.cpp: In function 'int main()': main.cpp:33:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("dfs.in", "r", stdin); ^ main.cpp:34:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("dfs.out", "w", stdout); ^