Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:45:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0;i < g[node].size();i++) ^ user.cpp: In function ‘void read(int&)’: user.cpp:26:42: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff,1,Mn,stdin),pos = 0; ^ user.cpp:34:42: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff,1,Mn,stdin),pos = 0; ^ user.cpp: In function ‘int main()’: user.cpp:51:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("euler.in","r",stdin); ^ user.cpp:52:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("euler.out","w",stdout); ^