Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:14:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < g[i].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:25:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.in","r",stdin); ^ user.cpp:26:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.out","w",stdout); ^ user.cpp:31:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] int x, y; scanf("%d%d", &x, &y); ^