Compilare: main.cpp: In function 'int main()': main.cpp:98:7: warning: variable 'ans' set but not used [-Wunused-but-set-variable] Div ans = dfs(1); ^~~ main.cpp:84:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("comp.in", "r", stdin); ^ main.cpp:85:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("comp.out", "w", stdout); ^ main.cpp:88:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ main.cpp:91:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &u, &v); ^